The essential doctrine of the christian faith is the doctrine of salvation. This is also probably the most controversial aspect of the christian faith. The doctrine holds that Jesus Christ died on the cross as a substitute for the sins of mankind and that all who accept him are able to be washed clean of their sins by his spilled blood. This begs the question, though, of just how much Jesus Christ is willing to forgive. If a child molester accepts Jesus Christ as his savior, but then goes and molests another child - is he still forgiven? Jesus Christ forgive sins that easily? If a husband accepts Jesus Christ as his savior, but then commits adultery against his wife, does Jesus still let him into heaven ahead of the man who didn't accept Jesus but didn't cheat on his wife? What exactly are the various shades of forgiveness? The question that I want to pose is what if Adolf Hitler had accepted Jesus Christ before committing suicide... would he then enter into heaven forgiven of his violent atrocities? Exploring these questions gives us a better chance to understand exactly what it is we believe and why we believe it.
Paul, the author of many of the epistles found in the New Testament and the chief apostle most responsible for spreading Christianity in early A.D. boastfully would claim that he was the "chief of sinners". What he meant wasn't that he was the chief of sinners, but that he had been the chief of sinners. The point that he was making was that Jesus Christ could take the absolute worse - such as himself - and still redeem them into the original innocent creation that they were meant to be.
Does this apply to Adolf Hitler? Certainly many would agree that Hitler embodied a degree of evil rarely found in the world. Would Jesus Christ really forgive him if he asked for it? The difficult, but also powerful, christian answer is that yes he would. Except this presumes a few things: it presumes that Hitler really wanted forgiveness and wasn't merely attempting to selfishly get into heaven. The New Testament is clear that it requires a true commitment of the heart in order to qualify for salvation, and that otherwise the prayer for forgiveness would be empty of any power. If Hitler didn't really mean it, didn't really feel sorrow for his sins and desperately want to repent - then Jesus, knowing his heart, would not forgive him. The second thing this presumes is that, if Hitler had really meant his prayer and was granted forgiveness, then after Christ has forgiven Hitler he would begin a process of sanctification. Salvation comes through prayer, but after salvation comes sanctification. This is the process where we are rid of our sin nature and a Christ-nature is built into us. It takes time and experience for this to happen.
A mark of a true christian life is sanctification. The product of sanctification is the fruit that he produces. It is how a christian is known. By his fruit. This is what happened with Paul. He started out as a persecutor of Christians, almost a parallel of Hitler on a lesser scale (though equally immoral), but was taken by Jesus, forgiven and transformed, and a work of sanctification was begun in him. Until we eventually reach the man who was able to write the most well known biblical passage on love: Corinthians 13. This passage is hailed as the greatest passage written on love in all of literature. That is the man who could honestly claim to be the "chief of sinners" but after Jesus had gotten into his heart he grew to know all about love. Jesus Christ forgive sins? Paul would say that he does so much more than that. He scrubs the sin away, and then paints love all over the recipient's life.
So, to answer the question - would Christ forgive Hitler if Hitler asked for it? Yes. If Hitler honestly wanted forgiveness he would receive it. More than that though - Jesus would take Hitler and transform and sanctify him until he was Christ-like. Because that is what the christian doctrine of salvation is about. It isn't simply about saving us from hell, but saving us from our sin nature, and teaching us virtue and love instead.