Why Was C.S. Lewis Not a Christian?

Matthew 24:34 (NKJV) "Assuredly, I say to you, this generation will by no means pass away till all these things take place."

C.S. Lewis said, "The apocalyptic beliefs of the first Christians have been proved to be false. It is clear from the New Testament that they all expected the Second Coming in their own lifetime. And, worse still, they had a reason, and one which you will find very embarrassing. Their Master had told them so. He shared, and indeed created, their delusion. He said in so many words, 'this generation shall not pass till all these things be done.' And he was wrong. He clearly knew no more about the end of the world than anyone else. This is certainly the most embarrassing verse in the Bible." (Essay "The World's Last Night" (1960), found in The Essential C.S. Lewis, p. 385)

C.S. Lewis, therefore, rejected the deity of the all-knowing and sinless (no falsehood) God of which Jesus was the 2nd Person in the Triune Godhead.