Here’s an explanation of what it was.
The Jefferson Bible, or The Life and Morals of Jesus of Nazareth as it is formally titled, was an attempt by Thomas Jefferson to glean the teachings of Jesus from the Christian Gospels. Jefferson wished to extract the doctrine of Jesus by removing sections of the New Testament containing supernatural aspects as well as perceived misinterpretations he believed had been added by the Four Evangelists. In essence, Thomas Jefferson, along with other founding fathers, did not believe in Jesus’ divinity, the Trinity, resurrection, miracles, or any other supernatural aspect described in the Bible.
In the reddit comments someone posted the C.S. Lewis quote about how you can’t separate Jesus from his teachings saying he was a good man but not the Son of God, because he didn’t leave that option. Lewis says it better than I can summarize it.
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 His being a great human teacher. He has not left that open to us. He did not intend to.
A fair portion of the comments then delve into the validity of Lewis’ arguments.