To a friend who believes that Jesus was a teacher who taught some good things but wasn't the Son of God.

I gather that you would say that the stories of Jesus' followers seeing Jesus after he rose from the dead and touching the scars of his crucifixion and Jesus eating food (Matthew 28:1-9, John 20:24-29, Luke 24:36-43) are not historical. It would presumably follow that Jesus' teachings about his resurrection (e.g. Matthew 17:7-13, Luke 18:31-34), would be equally false.

If this is so, how do you distinguish between the "many good things" that Jesus taught, and the falsehoods that the Bible records him as having said? And if the authors of the Bible were so free in altering what Jesus said to suit their own purposes, how is it that they didn't also write themselves into the story in a more favorable light? These passages clearly state that the disciples had no clue what Jesus was talking about when he taught about his resurrection and had no expectation of a resurrection actually happening after Jesus was crucified. If they were free to portray Jesus as more powerful than he actually was, wouldn't they have also shown themselves as wiser and more understanding than they actually were?

Even more mysterious, though, is the kind of hero that the authors of the Bible portray Jesus to be. A crucified messiah was incomprehensible to the Jews of Jesus' day, who fully expected a messiah who would throw the Romans out and reestablish a Jewish kingdom. The question the disciples asked in Acts 1:6 reflects this expectation, and the advice of the Jewish teacher Gamaliel in Acts 5:33-43 shows that there had been many individuals who had claimed to be messiahs of that sort. But for a messiah to suffer the humiliation of crucifixion was an absolute absurdity to the Jewish mind.

On the other side, a resurrected religious leader was no less absurd to the Greco-Roman thinkers of the day. To them, the body was the source of evil, and death provided a deliverance of the spirit from the evil of being embedded in a body. To be raised back to bodily life would have seen by them as a horrible thing - consigning the spirit to more life imprisoned in a body and enduring its evil. It was inconceivable to them that a religious leader could suffer such a fate. Paul encountered this line of thinking when he spoke to the philosophers in Athens in Acts 17:16-34. As Luke records the event in Acts 17:32, "When [the philosophers] heard about the resurrection of the dead, some began to ridicule him. "

So the authors of the Bible managed to make Jesus a hero who would have been ridiculed by both the Jews and the non-Jews of the day. If ever there has been a recipe for a failed religion, Christianity should be a prime example. But it's not. The only explanation I can come up with for why Christianity didn't die with Jesus' crucifixion is that it's actually true. Do you have a better explanation?