C.S. Lewis, Mere Christianity

We can all understand how a man forgives offences against himself. You tread on my toe and I forgive you, you steal my money and I forgive you. But what should we make of a man, himself unrobbed and untrodden on, who announced that he forgave you for treading on other men's toes and stealing other men's money? Asinine fatuity is the kindest description we should give of his conduct. Yet this is what Jesus did. He told people that their sins were forgiven, and never waited to consult all the other people whome their sins had undoubtedly injured. He unhesitatingly behaved as if He was the party chiefly concerned, the person chiefly offended in all the offences. This makes sense only if He really was the God whose laws are broken and whose love is wounded in every sin. In the mouth of any speaker who is not God, these words would imply what I can only regard as a silliness and conceit unrivalled by any other character in history.
[. . .]
I am trying here to prevent anyone saying the really foolish thing that people often say about Him: "I'm ready to accept Jesus as a great moral teacher, but I don't accept His claim to be God." That is the one thing we must not say. A man who was merely a man and said the sort of things Jesus said would not be a great moral teacher. He would be either a lunatic -- on a level with the man who says he is a poached egg -- or else he would be the Devil of Hell. You must make your choice. Either this man was, and is the Son of God: or else a madman or something worse. You can shut Him up for a fool, you can spit at Him and kill Him as a demon; or you can fall at His feet and call Him Lord and God. But let us not come with any patronising nonsense about Him being a great human teacher. He has not left that open to us. He did not intend to.

[Book II, Chapter 3, "The Shocking Alternative"]