This is a classic argument for Christianity known as the Trilemma. It was popularized by C.S. Lewis who wrote,

"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."

—Lewis, C. S.. Mere Christianity (C.S. Lewis Signature Classics) (p. 52). HarperCollins. Kindle Edition.

In his book More Than A Carpenter, Josh McDowell does an excellent job of expanding on this idea. I've tried to summarize the main points with this cartoon. McDowell set out to expose Christianity as false, but after a long period of investigation he was forced to conclude that the evidence for Christianity is very strong. This argument is just one chapter in his book. It's a small, easy to read paperback I highly recommend.