Let me explain, as best I can, what the skeptic has to deal with in this debate. According to the accounts, Christ was executed by crucifixion, dead and buried. The crucifixion was instigated by people in the Jewish leadership, and carried out by the Romans. Yet, within a short time, you have a bunch of people, starting in Jerusalem, and working their way outward to the rest of the empire. Peter, in Acts, makes this statement at the Gate of Jerusalem:
If we are being called to account today for an act of kindness shown to a man who was lame and are being asked how he was healed, then know this, you and all the people of Israel: It is by the name of Jesus Christ of Nazareth, whom you crucified but whom God raised from the dead, that this man stands before you healed.
In other words, he is telling the people responsible for the crucifixion of Jesus that Jesus had been resurrected, and therefore vindicated. Even if these accounts are were not completely accurate, the presence of people so firmly convinced that Jesus was resurrected that they were willing to risk a similar fate needs explanation. It is extremely difficult to resist the conclusion that the people who promulgated this message were profoundly convinced of the resurrection, because they were literally betting their lives on it.
Of course, there are people who think there was no historical core to the Christian message, and that Jesus never even existed. But this is an extreme position that most skeptics find don’t find defensible, and it makes it even more difficult to explain the spread of Christianity through the Empire.
Unless the extreme skeptical position is defensible, how do we explain the spread of Christianity? If the body was stolen, who would do it, and why would they. Some people have tried to say Jesus survived his crucifixion, but that seems really implausible. To say everyone forgot where Jesus was buried and went to the wrong tomb doesn’t make much sense either. Hallucination theory explains the Christian movement without making the movement and out and out fraud.