What is the Gospel?

"Gospel" is from old English roots meaning "good news". The Gospel is the heart of the Christian message: that Christ died for us, and that through him we can be reconciled to God and live in communion with him.
Unfortunately, the good news has to be preceded by bad news, since the answer does not make sense without the problem.
This document is divided into two parts, which get increasingly technical. The first part presents the basic Protestant view of the Gospel. I apologize to my Catholic and Orthodox readers. I originally tried to produce a "neutral" description, that took into account both Protestant and Catholic approaches. The result was so complex that I didn't think anyone could make sense out of it. Thus I'm using Protestant terminology, with a note at the end on differences.
Thus the second section of this document covers differences between the Protestants and Catholic approaches to salvation. I don't know enough about the Orthodox approach to describe it.

The Problem of Sin
Christians see the world as in a state of rebellion against God. Most people agree that there are problems in the world: it is full of suffering and injustice. Many diagnoses have been proposed. The primary problem may be a distorted relationship between capital and labor, unresolved conflicts from childhood, or people who are not properly educated in the human values of tolerance and cooperation. Thus attention may be focused on economic relationships, social structure, psychological therapy, or education.

Christians focus attention on the human relationship to God. They believe that the most serious problems result from the fact that human beings have lost sight of their proper relationship to God and each other. This is often expressed in moral terms. Because it is our obligation to obey God, we are currently in a situation of rebellion against him. This state is referred to as "sin". Individual actions of disobedience are referred to as "sins".

Although this moral perspective is correct, it should be noted that people often don't start out intending to be evil. Typically sin consists in choosing something that appears to be an immediate benefit. Thus it may be as much short-sightedness as anything else. This short-sightedness is aided by pressures of various sorts from outside.
Unfortunately, however it starts, sin is self-perpetuating. The further we get from God, the more distracted we become by secondary concerns, and the less likely it becomes that we will be able to find a way out.
For these reasons, sin can be seen both as intentional rebellion and as analogous to a sickness. It has elements of both.
It is unlikely that Christianity will make much sense unless you accept this diagnosis. If you still believe that you're basically OK, but just need more opportunities, or better education, Christianity doesn't have much to offer. It's like dealing with alcoholism or any other addiction: the victim has to understand that he is addicted before much can be done to treat him. Indeed sin can be seen as an addiction.

From a Christian perspective, the 20th Century can be seen as a set of attempts to try out alternative diagnoses. We've seen attempts to fix society based on changes in economics (Marxism), and eliminating corrupting influences (Naziism). We're now seeing a massive attempt to use a model that is basically therapeutic. Christians believe that these are all different ways to avoid taking personal responsibility for decisions, and recognizing that more often than not we get things wrong.
Christians believe that God created the world with certain specific relationships in mind. These form an ordered network of relationships to God, one's family, friends, neighbors, and even enemies. Family, friends, country, business relationships, and self are all important parts of the picture. But as soon as one or more is allowed to take the place of God, the entire set of relationships becomes unbalanced, and chaos results.

Original Sin
Christian theology traces this state of alienation from God back to Adam and Eve. The Bible portrays Adam and Eve as the first human beings. They were created by God. All humans are descended from them. They were originally in perfect fellowship with God and with each other, living in the Garden of Eden. However at some point they broke a command by God not to each the fruit of a certain tree. This seems to have been symbolic of a desire to be independent of God. This constituted the first sin.
As result of this sin, Adam and Eve were ejected from the Garden of Eden, and brought into the world as we know it now. The sin affected their very nature. They became subject to death and suffering. These effects were passed on to their children, and hence to us.

The effect that is relevant to this article is "original sin". Original sin says that all human beings are incapable of following God's will, until God has regenerated us. This inability is a result of the degeneration of human nature that resulted from the first sin.
Many Christians now regard some aspects of this story as symbolic. However the basic concept that we are incapable of following God's will until we have been regenerated is essential to Christian theology. This is referred to by several terms: "original sin", "total depravity", and "total inability".

The term "total depravity" is likely to be misleading. It suggest that human beings are as evil as possible. That isn't the intent. The image of God was not wiped out by original sin. Thus people are certainly capable of doing good things. However original sin corrupted us to the extent that nothing we do is ever completely pure. Our motivations are always mixed with selfish desires. This means that nothing we do can be in the strict sense righteous or meritorious.
Now we're ready for good news. The good news is that God is ready to deal with sin. He is ready to forgive and to "regenerate" us.
Forgiveness is one of the major themes in Jesus' teaching. Indeed it's one of the things that got him in trouble. He was willing to forgive people who were regarded as unforgivable. The standard examples were prostitutes and tax collectors. (Tax collectors were considered sinners because they were collaborators with the Romans, and were most commonly corrupt.)
However there are several things that we need to notice about Jesus' forgiveness. The first thing to notice is that Jesus' forgiveness generally comes at the beginning of his encounter with a person. Normally people didn't come to him asking for forgiveness. Rather, Jesus called them. This is important because of the observation I made above that sin tends to paralyze us. We are incapable even of realizing our situation. Thus God must take the initiative. This is shown in the way Jesus dealt with people.

The second thing to notice is who forgiveness was given to. Jesus forgave sinners and tax collectors. However he had harsh words for many of the leaders. These harsh words seem to be based on two things: self-righteousness and abuse of power. He says on a number of occasions that he came to call sinners, not the righteous. It is fairly clear in context that what he meant by "righteous" was those who felt that they didn't need God's help. The "sinners" that he forgave were all people who knew very well that they were sinners, and in need of forgiveness.

The third thing to notice about those Jesus forgave is that they responded with repentance. "Repent" is a word meaning "turn around". When someone repents, they regret what they have done. But more importantly, they reject it, and start going in the other direction. When Jesus forgives people, they often say things like "If I have defrauded anyone, I will pay back four times as much".
Finally, notice that forgiveness is connected with Jesus personally. This is not as clear during his life, since at that point people weren't in a position to understand about his death and resurrection. But even then, Jesus tended to forgive on his own authority. The Gospels note that this caused problems: he seemed to be pronouncing forgiveness in a way that only God should do.
During his life, Jesus called people to be his followers. He talked about our goal as entry into the "Kingdom of God." He saw it as his role to provide our entrance.

After his death and resurrection, Christians said that our forgiveness is based on his death for us. This seems to be based on Jesus' own teaching. It appears that he applied the "suffering servant" passages in the prophet Isaiah to himself. In these passages, someone (or possibly some group) suffered for the whole nation. On the night before he was killed, he told his disciples that his death was "for the forgiveness of sins".
Paul's letters talk about being "in Christ". This implies that we have a continuing relationship with Christ. This relationship is based on his bearing our sins in death, and our continuing role as his disciples. The term "disciple" refers someone who follows an individual teacher. It implies a high degree of personal commitment on both sides.
To summarize, forgiveness
Is based on Christ's death and resurrection, and our relationship with him as disciples.
Is given by God before we are even prepared to ask for it.
Is only possible for people who are willing to depend upon God to help them, rather than their own righteousness.
Is accompanied by repentance, which leads to a new life.
One-time and Ongoing Aspects of Forgiveness
Notice that there are both one-time and ongoing aspects to this. There is a sense in which forgiveness is a one-time event. It is given before we have done anything to deserve it. It is based on Christ's death for us. Since it happens before we are in a position to deserve it, it doesn't stop if our failures make us no longer deserve it. Since it is based on Christ's death, we could even say that our sins were all forgiven in 33 AD.

This one-time aspect of forgiveness is called "justification". The term justification is originally a legal one. It refers to "being declared innocent". This one-time aspect is reflected in Christian baptism. Baptism makes visible God's act of applying Christ's death to us, bringing us into contact with the power of God's forgiveness. It marks the beginning of our life as a disciple of Jesus.
However there is another sense in which forgiveness is an ongoing thing. God starts dealing with our sin as soon as we are "in Christ". However this process doesn't finish until we die. Thus we continue to sin, and we continue to need repentance. This ongoing process is called "sanctification", that is, "being made holy".
Jesus' life and teachings set before us a model of what life should be like. Any serious self-examination in the light of these standards will make it clear that we need to repent. I would maintain that repentance is in many ways the key to Christian life. It is the basis for real change in our lives.

Note that justification and sanctification do somewhat different things. Justification happens before we are even in a position to repent. It is based entirely on Christ's death for us, not anything we have done. This is more than just a legal fiction: Christ's righteousness is available to us because of the fact that God has established a spiritual bond between us and Christ. However it's based only on Christ, not anything in us.
Of course this isn't the end. God will not stop before we are completely healed of sin. This is sanctification. Until the end of our lives, our own situation is going to continue to be unreliable. Yes, God is dealing with our sin, and we are in the process of healing. But there are going to be periods during which we slide back. That is why we need repentance and forgiveness on an ongoing basis.

However this ongoing process happens in the context of a relationship that we can rely on. When God initially decides to forgive us and regenerate us, he unites us with Christ. This allows our relationship with God to be based on Christ's righteousness, not our own still unreliable spiritual state. Thus justification provides a reliable basis on which God can deal with us as we are slowly healed.

We respond to God's initiative by trusting him and committing ourselves to his care. This response is called "faith". Note that this is a special use of the word "faith". Faith is sometimes used to mean a kind of belief. In Protestant thought it has a more personal meaning. It is our whole response to God's initiative on our behalf.
You will sometimes hear the phrases "justification by faith" and "faith alone" (or the Latin "sola fide"). Sometimes it sounds like God is rewarding us for believing in him. But that's not what the phrase means. It actually refers to the way that we receive justification, not the reason God justifies us. Faith is the way we participate in the bond that God has established between us and Christ.
Justification by faith means that we rely completely on God for help. We are grateful for what he has done for us, and trust him to heal us of sin. "Justification by faith" is really the opposite of "self-righteousness". It is the attitude that we find in those Jesus forgave.

Faith shows itself in repentance and changed lives. While we do not expect Christians to become immediately perfect, through faith we have a new life in Christ. Where there is no new life, we can reasonably conclude that justifying faith is not present. Jesus talks about knowing things by their fruit, i.e. by the results that they produce.
No matter how far we have progressed, we still live in dependence upon God. We grow in goodness by continually allowing Christ to work more completely through us. The ideal is a sort of "transparency" to God's will. That does not, of course, mean that we disappear as individuals, but that individuals find their fulfillment by focusing on God and others.

Christ's Role
I'd like to focus a bit more on Christ's role in our transformation. What we are unable to do for ourselves, because of our addiction to sin, Christ can do for us. There is an underlying concept here that is somewhat foreign to many people in the 20th Century. We tend to think of individuals as independent. Ideas of spiritual community or solidarity do not come easily to us.
One of the most interesting Christian writers I've read is Charles Williams. He has written a set of novels, as well as an interpretation of church history. In these, he maintains that the basic principle of Christianity is "exchange". He believes that Jesus is speaking quite literally when he tells us to "bear each other's burdens." It is possible to share and even take from another their guilt and fear, as well as of course to share joy. Thus Christ working in us is just one example (although of course a unique example) of a kind of thing that we can do for each other.

The well-known poem by John Donne, "No man is an island", expresses much the same thing: there is a spiritual communion by which what happens to one happens to all. It is this idea of spiritual solidarity which forms the background for Christian beliefs in this area. It permits us to think of Christ as bearing our sins, us being credited with Christ's righteousness, and Christ becoming alive through us.

While God is anxious to forgive us and help us reestablish proper relationships, something has to happen to make that forgiveness and regeneration real. Christians have regarded Jesus' death as doing that.
In the first century, this didn't seem to require much explanation: the concept of sacrifice was common to all religions. Thus the idea of sacrifice for all of mankind made sense. In the 20th Cent., the concept is not so obvious. Thus I feel some need to talk about why sacrifice should be needed.

Ultimately I believe the requirement is part of the spiritual structure of the universe. I probably can't explain why it's there any more than I can explain why the physical laws are as they are. However I will try to say a few things anyway.
First, Jesus' death helps us understand the severity of our sin, and bring us into the condition where God can work with us. The fact that God's son would die for me makes it very clear how radical my need for change is.
In human relationships you will note that it is often difficult to reestablish trust once a relationship has been broken. Normally both sides have some work to do. Apologies may be needed, often on both sides. But often the person who is doing the forgiving must do something to show its reality. In many cases one can't just forget what has happened. If the break involves important or sensitive issues, reestablishing the relationship is likely to require an action that has some personal cost.
It is that way in our relationship with God. God can say that we are forgiven. But in order to reestablish the relationship, something more is needed. In this case, only God is in a position to take the necessary action. Because of the severity of the problem, it is appropriate that the cost would be in blood.
Christian theology only makes sense if you believe in the sort of spiritual relationship between people I referred to above. In particular, of a spiritual union with Christ. Redemption is a spiritual rebirth. This comes through being "in Christ" (to use Paul's favorite term).
For those who are united to Christ, his death and resurrection become our death to sin and rebirth as his disciples.
One of the effects of sin is to isolate us, both from each other and God. Christ joined us on our side of that wall of isolation, accepting all of its consequences. Since he is with us on our side, the wall no longer separates us from God and each other.
A balanced Christian approach should look at both Jesus' death and resurrection. It is possible to overemphasize either. If we focus just on his death, we can end up with a cult of death and suffering. We need to remember that Christ was victorious over death, and through our union with him, we will ultimately be victorious over sin and death.
However if we focus just on the victory, and forget the cost, we can end up with a Christianity that has no depth, and cannot help people cope with suffering.

Union with Christ
In this section, I've repeatedly used terms such as "union with Christ". Paul's letters are full of language like this: "So if anyone is in Christ, there is a new creation: everything old has passed away; see, everything has become new!" (2 Corinthians 5:17) Many Christians talk about having a "personal relationship with Jesus Christ."
What does all of this mean? There is a range of answers. Classical Protestantism sees our relationship with Christ as primarily based on objective matters, not on private religious experience. The foundations are Christ's death for us, his call to us to be his followers, and his love for us. We participate in it by our faith and trust in him, and the fact that we are committed to him as disciples. We learn his will for us primarily from Scripture, although we are certainly guided by prayer.
However many Christians have a more experiential orientation. For them, our relationship is based on a "conversion experience." In some traditions this is followed by a "baptism in the Holy Spirit", which is evidenced by ecstatic behavior such as "speaking in tongues". Christians are expected to have a continuing experience of Jesus in our heart, loving us and guiding us. This mystical communion is described in terms that would be familiar to mystics in all religious traditions.
I'm not as familiar with Catholic piety, but I believe that it has a similar range, with the addition that Mary is also available as an object for religious experience. Of course the terminology is sometimes different.
The Church has had an ambivalent attitude towards mysticism. Its emphasis on personal experience can be valuable. Without it, Christianity can sometimes turn into a purely intellectual or legal matter, which people have a hard time getting excited about. However mysticism often pushes the boundaries of orthodox thought, and sometimes goes beyond it. In valuing individual experience, it can sometimes devalue the world and our actions in it. When it goes too far, it removes the objective criteria for right and wrong, making private religious experience the primary goal.
My personal approach is closer to the Reformers'. Among other things, I am concerned about maintaining consistency with what Jesus actually taught. Some scholars have made a case that Christianity quickly abandoned any connection with Jesus' actual message, turning him into the center of something like the "mystery cults" that centered around various mythical religious figures at the time.

Some Christian practice does go beyond anything Jesus seems to have envisioned. However I believe it is possible to base the Christian life on his teaching. Jesus called people to be his disciples. He expected them to trust in him and follow him. He spoke of the "Kingdom of God", but in a way that implied that he was empowered to bring people into it. He said he was dying to establish a new covenant for the forgiveness of sins. However he also pointed away from himself to God as Father.

The explanation above is based on Protestant terminology and analysis. Catholics have a somewhat different description of the process of salvation.
Catholics and Protestants agree about many fundamental issues:
The nature of sin
God must initiate the process of salvation
Salvation is based on Christ
The Christian life requires us to continually compare our lives with Christ's standards. This requires repentance and change.
The primary differences involve the specific way justification and sanctification are thought of. First, Catholics use the term "justification" to cover both what Protestants call justification and what they call santification. There is also a difference in how they use "faith". For Catholics, faith tends to mean just belief. For Protestants, it is a wider term, including our trust in God and our commitment to live as his children.
These differences caused enormous confusion during the 16th Century. When Protestants talked about "justification by faith alone" they meant that we rely on God alone for salvation. However justification is always accompanied by sanctification, which is the term that covers the transformation of our lives. Because of difference in definition, Catholics took "justification by faith" to mean we could be saved just by having an intellectual belief, without any real change in our lives.
When these differences in terminology are sorted out, there are great similarities in what is being said. However there are still some differences. Protestant theology sees us as being saved by something outside of us: Christ's death and resurrection are applied to us through faith. Catholic theology sees salvation as the final result of a process of transformation that happens by

God's grace.
Both of us agree that Christ's death and resurrection are applied to us, and both of us agree that our lives are transformed by God's grace. Thus it is possible to view these as complementary emphases. However they are sufficiently different that there are real implications for our lives.

Protestants see the basis of our relationship with God as being outside ourselves. All of our spiritual resources come from Christ, and are applied to us by the Holy Spirit through our union with him, making full use of tools such as the preaching of the Gospel and the sacraments. Because the basis is outside us, our status as God's children doesn't depend upon our current spiritual state. If we stumble, God is there with the appropriate mixture of discipline and encouragement. We remain his children.
Catholics see the basis of our relationship with God as being a supernatural grace that is active in us. While this grace comes from God, it is infused into our souls. Certain serious sins ("mortal sins") are incompatible with continuing to be in this state of grace. Thus reconciliation "necessitates a new initiative of God's mercy and a conversion of heart which is normally accomplished within the setting of the sacrament of reconciliation" (Catechism of the Catholic Church, 1856). Because sin has largely broken our relationship with God, we look to the Church for help in reestablishing it.
There are several emphases here, which all of us accept:

that we are made participants in Christ's death and resurrection through the action of the Holy Spirit
that we are renewed by the Holy Spirit, so that we are spiritually transformed, and made able to do good works
the importance of means such as preaching and the sacraments in helping us grow in the Christian life
However Protestants make the first primarily responsible for our continuing status as God's children, while Catholics make the last two primarily responsible for this. This has both conceptual and practical implications. Protestants tend to focus on Christ for spiritual resources, and to see the relationship with him as unbreakable (even if it turns to discipline when we sin). Catholics tend to focus on a supernatural grace which is infused into us, and to the role of the Church in dispensing grace through the sacraments. That grace may no longer be active after certain kinds of sin.
Imputed Righteousness vs. Infused Grace
This difference is summarized in the terms "justification by faith" and "imputed righteousness", to represent the Protestant approach, vs. "infused grace", to represent the Catholic one.

While Catholics certainly accept the importance of faith, there is no direct equivalent of Protestant "justification by faith" in Catholic theology. Catholic theology does not accept that our relationship with God continues to be in full force even after mortal sins. These are sins that are serious in themselves, and where the person committing them knowingly rejects God's will. Mortal sins involve a rejection of the supernatural grace that is established by baptism. While they do not undo baptism, they do mean that we are no longer in a state of grace. A state of grace may be reestablished by the sacrament of reconciliation. This sacrament includes confession of the sin, repentance, and forgiveness.

Their concern is that the Protestant approach (of saying that our justification establishes an unbreakable relationship with God) would tend to encourage moral and spiritual laxness, since it means that our base relationship with God is not contingent on continuing progress in the Christian life. So for Catholic theology, our relationship with God depends upon a certain level of continuing cooperation on our side.

Catholics do acknowledge a certain one-time aspect to this process. It is represented by baptism. Catholics believe that baptism places an indelible mark on the soul, and that it begins the work of regeneration with us. Baptism is not undone, no matter what we do. Thus in some sense Catholic baptism may play a role that is analogous to Protestant justification. Both are one-time things that start out our relationship with God. But for Catholics, maintaining that relationship depends upon our continuing cooperation, while for Protestants, justification is permanent.

Protestants think of God as a father, who will continue to care for them and help them even when they fall short. Like a human father, he does exercise discipline. Thus an unconditional relationship with him doesn't mean that he ignores sin. But he does not disown his children. He deals with our sins -- even serious ones -- in the context of an unconditional commitment to us. The point where we have committed a serious sin is precisely the place where we need God the most.

When we have committed a serious sin, we need to be reconciled with God. For Protestants, sin does not completely break our relationship with God. Thus reconciliation comes from God, working through our bond with Christ. While sin may greatly strain that bond, it does not break it. For Catholics, serious sin breaks the bond of charity between us and God, as described above. Because sin has largely broken our relationship with God, we look to the Church for help in reestablishing it. Of course Protestants also believe that God works through visible means, so the preaching of the Gospel and the sacraments are important tools that God uses to restore us.

In technical terms, this difference is referred to as "infused grace" versus "imputed" righteousness. The first represents the Catholic position. It indicates that in salvation, grace comes to be present in us. We remain in a state of grace only as long as by our continuing cooperation, this infused righteousness continues to be present. It is a supernatural gift, meaning that it's not something we could develop on our own. That's the reason that it ceases to be present after mortal sin.
The term "imputed righteousness" represents the Protestant position. It emphasizes that that our righteousness comes solely from Christ. The term "imputed" (as well as the related term "forensic justification") suggests almost a legal fiction: that Christ's righteousness is credited to our account even through we have none of our own. While this is description is correct, calling it is fiction probably is not. That fails to take into account the fact of our union with Christ. His righteousness is really present in us because we are "in Christ". However it always remains his. In Protestant theory, we never develop any righteousness that is properly speaking our own. The goal of Protestant piety is transparency to Christ.

Heaven: Our Intended Destination
Based on Jesus' teachings and other sources of revelation, Christians believe that God created human beings to live eternally in fellowship with him. The future as described in the Bible includes the resurrection of all people, a judgement, and eternal life in either heaven or hell.

Christians are not agreed on the exact details of how this will happen. However the differences tend to involve details of timing, and other issues that don't seem worth dealing with here.
The fact that human beings are created with an eternal destiny should have a significant impact on our priorities. It often seems that governments, nations, and other institutions are the enduring feature of human history, and people are transient elements. Christianity says that this is radically wrong. One cannot treat people as disposable adjuncts to the nation or other institution: ultimately it is the people who matter.

Note that there is a subtle difference between resurrection and the existence of an eternal soul. Many religions have held that human beings have an immaterial soul, which does not die when the body does. Christians generally agree with this (although a small number do not). However the distinctive Christian doctrine is not the eternal nature of the soul, but the resurrection of the body. Humans are unified beings. The body is an essential part of the person. In heaven there will be some analog of the body.

Christians believe that there will be a judgement. In this, everyone's life will be evaluated. Those who depend upon Christ for salvation can be assured that they will pass this judgement. However the quality of their lives will still become known, and everything in their lives that was not built on Christ will be purged. The Bible talks of their work being tested with fire.
The Bible says that there are two different outcomes for eternal life: heaven and hell. There is not a precise description of either heaven or hell, nor are we told how many people will end up in each. They are described using terms that seem metaphorical: a city built of gold in heaven, a lake of fire for hell.

All major Christian traditions say that in the end everyone will end up in either heaven or hell. At first glance, it sounds like we won't be held accountable for what we did, as long as we manage to meet the minimal criteria for ending up in heaven. In fact there are several ways of maintaining some kind of accountability.
Catholics believe in something called "purgatory". This is a "place" (not necessarily an actual physical place, of course) where those who will end up in heaven are purified. Traditional Catholic theology says that when God forgives sins, he removes the guilt. However there may still be consequences. One of those consequences is that "temporal punishment" is still owed. The goal of this punishment is to be cleansed, and made fit for heaven.
Note that purgatory only applies to people who will be admitted into heaven. It is not part of hell, nor is it some kind of intermediate state between heaven and hell. It is in a sense the entranceway into heaven.
Traditionally, Catholics believe it is appropriate to pray for those that are in purgatory. These prayers, as well as masses said for them, etc, may in some way ease their process of purgation. This is one aspect of the general Catholic concept that those on earth and those in heaven retain a spiritual connection with each other. (This is called the "communion of saints".) Those on earth may ask for intercession from the saints, and may intercede for those in purgatory.
Protestants do not normally accept the concept of purgatory. There are several objections. Among the most important are
It implies that Christ's death for us isn't enough.
The Bible says in several places that any interaction with the dead is forbidden.
The concept was also discredited by various abuses with which it was surrounded in the 16th Cent. These made it look like the Church was selling salvation, or at least release from Purgatory.
Thus Protestants normally object to anything that looks like Purgatory, as well as prayers for the dead. It is often said that prayers for the dead suggest a lack of trust in God, since God will judge them justly.
You can see the difference clearly if you attend both Protestant and Catholic worship services. When someone in the congregation has died, Catholics will ask for prayers for them and their family, while Protestants will ask only for prayers for their family.

Despite the rejection of Purgatory, many Protestant groups are still concerned to maintain accountability for what has been done during life. Many Protestants believe that there will be different levels of honor in heaven. Many Protestants also believe that even saved people will go through a process where their entire lives are reviewed and judged, even though their final destination is not in doubt. This is sometimes described as the "bema seat judgement". As a result of it, Christ's followers will be rewarded according to the quality of their work. This is contrasted to the "great white throne" judgement, which determines whether someone will spend eternity in heaven or hell.

(I should note that the terms "bema seat judgement" and "great white throne judgement" are not standard among all Protestants. They are based on one specific eschatological system.)
Note that Protestants do believe that those who are in heaven have been freed from sin. However the way in which this happens is thought of somewhat differently. For Protestants, our righteousness comes from Christ, because we are united to him in faith. When our nature is perfected in heaven, this happens because our union with Christ is perfected, and his righteousness fills us fully.
The same difference occurs here as in the doctrine of justification: Catholic theology tends to envision the Christian life as due to the growth of grace in us, while Protestant theology tends to envision the Christian life as due to an increasing transparency to the presence of Christ. The doctrine of Purgatory seems oriented towards the Catholic description.

Why Does Hell Exist?
Currently there is a good deal of discussion among Christians about the morality of hell: it is said that a good God would not condemn people to an eternity of torture. However that has been the belief of most Christians through most of Christian history. It seems to be supported by the Biblical account. The alternative seems about as bad: that God will force himself on people who do not want him.

Note that it is not necessary to say that God imposes hell as punishment. It may be the automatic (indeed logically unavoidable) consequence of rejecting God. It is not clear that God makes it intentionally unpleasant. It may be the nature of the people who are there, and the fact that they are finally given what they want: freedom from God.
Many criticisms of judgement suggest that it is arrogant to say that Christian ideas are true and others are false. "How can you be so arrogant to believe that Christians will go to heaven and everyone else will go to hell." As we will see below, most Christians don't believe this. However the idea that this is arrogant seems odd. We do not criticize mathematics teachers for saying that 2 + 2 is always 4, and that believing sincerely in 5 is not acceptable. Either there is a God or there isn't. Either Christ died to save us or he didn't. If he did, it's hard to see how it can be arrogant to say so. If he didn't, then Christians are wrong, but not arrogant.

I would say that ultimately hell is a result of the "hardness" of created reality. Let me try to explain: Christianity believes that the universe has a real existence, and that it is distinct from God. (This is a specific position, which not all religions and philosophies accept. For some, there isn't a real distinction between God and the universe.) In order to provide us with a region in which we can make our own decisions and take our own actions, God set up a universe that operates under dependable laws. Possibly there are other ways he could have worked. But we don't know of any other way to set things up so that we have real lives of our own.

The existence of a real universe with dependable laws has consequences. One of those consequences is the fact that people can have incorrect ideas. If they misunderstand the way the universe works, damage may result. Most of us understand this in the realm of science and engineering. There is no reason that theology should be different. If there weren't any distinction between truth and falsehood, nor any consequences to error, we would be living in an amorphous mess (the metaphysical equivalent of "gray goo"). There would be no way to live sensibly.
The standard Christian position is that salvation is only available through Christ. This isn't because God is biased towards Christians. Rather, it's a consequence of the way the universe works. Heaven is by definition eternal life with God. But Christ is God's way of establishing relationships between human beings and himself. He is the divine logos, the agent of creation. It is inherently impossible to be with God without being in Christ. If a human being somehow managed to be in God's presence bypassing Christ, that person would be unmade.
The only alternatives I can see to hell are for God to arrange for everyone to accept Christ, or for him to destroy everyone who does not. As you'll see below, each of these alternatives has its supporters. However most Christians believe that if everyone ends up choosing God, human existence is a sham: God loaded the dice to such an extent that there were no real human decisions. Most Christians also believe that a part of us is immortal. For God to destroy it would be an interference in the created order that would seriously violate its integrity.
Before judging these issues, I'd ask you to look at some additional considerations.

Is Hell Unfair?
The standard Christian position is that anyone who rejects Christ will end up in hell. Does this mean that only Christians can be saved? The Catholic church and many Protestant churches don't think so. They believe it is possible that Christ can come to someone in an inward and spiritual way, even if they've never heard of Christ. Thus someone can be an "anonymous Christian." That is, they can know Christ spiritually without realizing it.
Most Christians also believe that God's judgement will take into account the sorts of opportunities a person had to learn the truth. A person who has never heard the Gospel can't be said to have rejected Christ. An even worse situation occurs when Christians have persecuted other groups. A person who sees Christ as a persecutor has hardly had a real exposure to the Gospel.
[Historical note: It's worth noting that two major classical Protestant writers thought it was possible for non-Christians to be saved: Zwingli and Wesley. Calvin did not.]

Alternatives to Hell?
There is a substantial minority view, which says that God will find some way to reach everyone. This is called "universalism". A few 20th Cent thinkers have also suggested that those who are not destined for heaven are simply destroyed. This is called "annihilationism".
Most Christians think that both of these alternative views are ruled out by teachings in the Bible. Jesus himself speaks of judgement, and of "Gehenna" and "the outer darkness".
While most Christians reject universalism and annihilationism as doctrines, many orthodox Christians hold positions that are very close. Let's look at them briefly:
There is no statement in the Bible about how many will be damned. When someone asks Jesus this, he deflects the question. He does say that the way to salvation is narrow, and that many follow the road to destruction. However we can still hope that in the end God will deflect those on the easy road to destruction. I believe universalism as a doctrine is unorthodox, but hope for all is possible.

A number of orthodox 20th Century writers point out that those who are in hell are not the same kind of people as those in heaven. Human beings are designed to live with God. In heaven our humanity is perfected. Hell is not described in any detail in the Bible. The descriptions that most people hear are based on speculative fiction, such as Dante's. However if humanity is created to be with God, then it is reasonable to believe that those who are finally separated from God in hell are less than fully human. Several writers refer to them as equivalent to "ashes", the remnants of what used to be a human life. Thus we may not have two groups of people living next to each other, with the saved watching the damned living in torture. Hell, whatever it is, has less reality than heaven. This is suggested by Jesus' most common way of referring to it. He calls it Gehenna. This was the garbage pit outside of Jerusalem, although the term also was used in discussions of the last judgement.
Could Hitler end up in Heaven?

Heaven and hell are not a matter of totaling up good deeds and bad deeds and seeing which predominates. From the Christian perspective, if it comes to merit, no one merits heaven, and we've all done enough bad for hell to be justified. However God doesn't want anyone to end up in hell. Anyone who depends upon him for rescue will be saved from hell.
There are several questions that are asked so commonly that I think they're work looking at here. Here are two examples:
Could Hitler end up in heaven if he repented at the last minute?
It seems unfair for God to save people just because they are Christians. There are lots of rotten Christians and lots of good non-Christians.
I'm going to try to deal with that whole class of questions here. Note that in doing so I'm going to make my own opinions a bit more obvious than I do elsewhere in these essays. I am quite sure that there are answers from Catholic and Orthodox perspectives, but I'm not in a position to argue convincingly from those viewpoints.

First, the Bible doesn't give us precise information as to who will end up in heaven or hell. We are warned particularly not to judge other people (except to the extent that we have specific responsibilities for church discipline or as officials involved with the legal system). This means that discussing specific people such as Hitler is dangerous. We don't know what is going on with individuals. Hitler looks particularly evil. But someone completely unremarkable may be just as evil, but may not have had enough political power to have the terrible effect that Hitler did. Perhaps Hitler was completely insane, and not responsible for his actions. (I seriously doubt it, but we don't know for sure what was going on in his heart.)
However more important, I need to warn you that heaven isn't a reward for being good. The basic Protestant model for salvation is as follows:

God chooses us
We respond with faith, which basically means that we rely on God for salvation
God forgives us, and simultaneously starts renewing us and getting rid of our sin
There is certainly a connection between faith and being good: Faith is our side of the bond that connects us to God. God will use that connection to regenerate us and get rid of our sin. The process isn't finished in this life, but it certainly is started. Christians should be better than if they weren't Christians. Jesus said that you will know his followers by the fruit that they bear.
It would be nice if we could say that the best half (or whatever) of mankind are Christians and the worst half are non-Christians. Unfortunately, I'm afraid it isn't going to be quite that neat. Some people become Christians late in their life, and so the process has only started when they die. Some Christians may be in more dangerous positions than non-Christians. Some Christians may have been born with really bad tempers, etc, which makes them look more evil than they actually are.
So I'd say that there should be real evidence of regeneration operating in the lives of Christians, but you shouldn't expect that all the people who look good are Christians and all those who look bad are non-Christians.

Here's one thing to think about: What happens to someone who is relatively good in this life, but who does not have faith? Unfortunately, he may end up in hell. In theory this person could be the best person who ever lived (except Jesus, who was without sin). The problem is that by not having faith, they do not have the connection through which God will take care of their remaining sin. Even though there aren't very many visible problems, they (and the underlying addiction to sin of which they are symptoms) can't be dealt with. Thus this person can't be made fit for heaven.

Now the obvious response to this is: so why shouldn't people just go ahead and be evil, if heaven isn't based on being good? While heaven isn't a reward for reaching a certain quota of good acts, you won't get in unless you have a relationship with God through which you can be renewed. Someone who says "let me be evil for my whole life, and repent at the last minute" almost certainly isn't going to be capable of repenting in any way that does him any good. In having that intention, he has already rejected the kind of faith that is needed for salvation.

Strictly speaking, heaven isn't even a reward for having faith. It's not that God is rewarding you for faith and punishing you for not having faith. Rather, it's that God uses a certain kind of relationship in order to make you fit for heaven. Faith is a key part of that relationship. If you're sloppy about building a bridge it may fall down. Nature isn't consciously punishing you. It's just the way the universe is built. In my view, one of the spiritual laws of the universe is that in order to end up in heaven, you have to have justifying faith (not just intellectual belief in the Trinity -- justifying faith means that you rely on and commit yourself to God as your savior).