Recently I read an exchange of views between freethinkers about whether there was a historical Jesus that gave rise to the legends, or whether the Jesus character was entirely mythical. I found myself entirely unmoved.
I went through the four gospels to collect everything Jesus is reported to have said about what we should DO, all of his alleged ethical teachings. I wrote up my findings here:
I don't see, or feel, any necessity to dispute the existence of a historical Jesus. I find that debate beside the point.
The "synoptic" gospels, Matthew, Mark, and Luke, present one picture of Jesus and his teachings, and the fourth gospel, John, presents a starkly different one. The synoptics present a Jesus who expected Judgment Day and the end of the world Real Soon Now, certainly within the lifetime of his contemporaries. Further, very few were to be saved when the Earth was destroyed; almost everyone would be going to a fiery Hell. It makes perfect sense that his ethical teachings, what he told his followers to DO, were radically unworldly. Abandon all your Earthly ambitions. Abandon your Earthly family and give your loyalty to your fellow believers. Sell everything you own and use the money to do good works. Avoid getting any Earthly reward for your good works. Follow the entire Law of Moses, follow the spirit of the Law as well as the letter. Overfulfill the Law, inside and out; not only abstain from killing but also from anger, not only abstain from adultery but also from lust. Love your enemies, Practice strict nonviolent pacifism. Do not judge others, that is not your job, Judgment Day will come soon enough. Concentrate on purifying your own character, strive to "Be perfect, even as your father in Heaven is perfect". This was asking a lot.
The gospel of "John" was apparently written AFTER that generation HAD passed away. The apocalyptic prophecies are removed, all of the radically unworldly ethical teachings are removed; the writers of John did an Apocalypsectomy. Since John, organized Christianity has not been about following Jesus' teachings, it has been about believing certain stories and creeds.
All this is evident from reading the texts; it really matters not at all if the texts were inspired by the experience of the writers listening to a real man named Jesus. The literary Jesus was an apocalyptic preacher, he expected the end of Earth soon, and told his followers to take radical action to prepare, to rack up as much credit as they could in the little time remaining, in the hope of being among the very few who would be saved. He was, apparently, wrong about that.
So there is no reason why we should bother disputing the exact origin of these texts.