Matthew 28:12-15 talks about a rumor that was circulating among Matthew's Jewish contemporaries: that Jesus' resurrection was a farce, since the disciples stole his body from the tomb while the Roman soldiers were asleep.
The New Testament classes I've taken posit a development in the resurrection stories. In Mark, which many scholars consider the earliest Gospel, there are no soldiers guarding the tomb. And so many scholars believe that Matthew inserted soldiers into his "Christ is risen" story to respond to a Jewish argument against the resurrection: that the disciples stole Jesus' body, which accounts for the empty tomb.
They get this from Matthew 27:63-64, in which the chief priests and the Pharisees tell Pilate: "Sir, we remember what that impostor said while he was still alive, 'After three days I will rise again.' Therefore command the tomb to be made secure until the third day; otherwise his disciples may go and steal him away, and tell the people, 'He has been raised from the dead,' and the last deception would be worse than the first" (NRSV).
But my issue with scholars on this point is that the rumor itself acknowledges that there were soldiers guarding the tomb. How could the disciples have stolen the body while the soldiers were asleep, if there were no soldiers at the tomb in the first place? And this was the rumor that was circulating in Matthew's day.
From Matthew, we see that even the Jewish opponents of Christianity believed there was an empty tomb. Could that be because there was one?
One interesting detail is this: In Matthew's story, the Pharisees were familiar with the idea that Christ would rise again, right after he died. Throughout the Gospels, however, the disciples did not expect Jesus' resurrection at all. They were disappointed after Jesus' death. Apparently, the Pharisees were paying more attention to Jesus than his disciples!