How did the myth of Jesus' resurrection originate?

[xpastor]

Many would answer that it was borrowed from the Osiris myth.

Perhaps. However, I start from the premise that Yeshua was a historical figure, an itinerant rabbi with considerable rhetorical prowess, who got himself crucified by the Romans and remained dead.

So my answer is cognitive dissonance.

When people believe something intensely, and it fails to happen, they can't live with that. They have to invent a story to prove that it really did happen in an unexpected way.

We have seen this in the recent history of apocalyptic prophecy. William Miller predicted that Jesus would return on October 22, 1844, and it obviously did not happen. The result was the birth of Seventh-Day Adventism, which "arrived at the conviction that Daniel 8:14 foretold Christ's entrance into the Most Holy Place of the heavenly sanctuary rather than his second coming." (Wikipedia) I have no idea what that is supposed to mean, but it satisfied them. Likewise, the first Jehovah's witnesses predicted that Jesus would return in 1914. When no one spotted him, they said he had returned "invisibly."

Jesus was an apocalyptic prophet expecting the Son of Man to come and usher in the Kingdom of God within his own lifetime.

Of course he died without seeing any such event. I suppose his followers said things like, "I just can't believe he's gone." Denial is the start of the grief process. Given Jesus' very real abilities as a preacher and the credulous nature of the era, they never moved on to the later stages of grief. Someone came up with the idea that he must have risen from the dead, and then others started to fill in the details, that so-and-so had seen him post-crucifixion, that there were angels there, that he showed his wounds, that he had dinner with his associates, that he ascended into heaven.

Christians will protest that no one would make up the story of the resurrection, but they do in fact come up with all sorts of fictional details to promote their faith. To take a few trivial cases, I have received an email which presents the young Albert Einstein as a defender of the Christian faith against his atheistic professor although Einstein was a non-observant Jew who explicitly disavowed any belief in a personal God. Or there is Lady Hope's well-known story of Charles Darwin's deathbed reversion to Christianity, although Darwin's children say she was nowhere near the great scientist in his last years.