A lot of people I talk to like to make the argument about Jesus that goes a little something like this, "Well, I can totally believe he was a prophet, that he was a good moral teacher, but I just can't believe he was God's Son, the Messiah... no, not that, it just seems so ridiculous."
I think C.S. Lewis in Mere Christianity gives the best argument for why this is perhaps the only thing one CANNOT say about Jesus (Skip the first two paragraphs if you just want the real core argument- the first two just contextualize it).
"Let's first take the claim to forgive sins: any sins. Now unless the speaker is God, this is really so preposterous as to be comic. 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 theirs sins were forgiven, and never waited to consult allt he other people whom their sins had undoubtedly injured. He unhesitatingly behaved as if He was the party chiefly concerned, the person chiefly offended in all 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.
Yet (and this is the strange, significant thing) even his enemies, when they read the Gospels, do not usually get the impression of silliness and conceit. Still less do unprejudiced readers. Christ says that he is "humble and meek" and we believe him; not noticing that, if he were merely a man, humility and meekness are the very last characteristics we could attribute to some of his sayings.
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 either be 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 His being a great human teacher. He has not left that open to us. He did not intend to."
At church Tim Keller often talks about how Jesus basically is the antithesis of what the world thinks of as a leader- He was humble and meek and submissive, while most other leaders seek power and fame and wealth. As new kingdoms and new administrations come and go, it's just a change in people, making tweaks within the same system. But Jesus called for an entirely new system. I mean think about it, what He was saying was entirely radical. To prize what the world calls pitiable and suspect what the world calls desirable? That is life-changing leadership.
It is entirely freeing (and not restricting, as some other people argue) to see Jesus as our substitute and realize that this world is not all we're living for, that our hope and joy and treasure and identity is not in anything of this earth- not wealth or acceptance or strength or power or fame. Our acceptance is a gift, freely given, and one we certainly don't deserve, for we all fall short and sin. And grasping that... is life-changing. As Tim Keller said, "If you see Jesus as an example, it will crush you, but if as a substitute, it will free you."
Still think he's just a good moral teacher?