Just as Josephus's response to the anti-Jewish polemic of Apion has inadvertently preserved the basic outline of anti-Jewish polemic in his day, Matthew's response to arguments against the early Christian claims about the resurrection preserves what must have been the basic charge of his day: the disciples stole the body (compare later sources in Stauffer 1960:144-45; Tert. Apol. 21). But it is exceedingly doubtful that disciples would deliberately steal the body yet later prove prepared to die for the claim that they had seen Jesus alive from the dead!
Jesus' enemies could not account for the body's disappearance. Indirectly this suggests that opponents of Christianity conceded that Jesus' body was missing and that no simpler explanation (such as the body's being deposited in the wrong tomb) was available (also Craig 1984; Meier 1980:356). Although Paul does not appeal to the empty-tomb tradition in 1 Corinthians 15, his account necessarily implies it. Many people in antiquity claimed to see "ghosts," but for Palestinian Jews "resurrection" meant bodily resurrection and nothing else. Against some commentators, it is quite difficult to imagine that the disciples would have begun proclaiming the resurrection, and the authorities opposing them, without anyone's having checked the tomb (Craig 1995:151). Yet the church depended on the testimony of witnesses of the risen Christ, not simply on an empty tomb (Ladd 1974b:325). The empty tomb tells us about the nature of the resurrection (and the body and history), but the witnesses attest to its facticity.
In contrast to the disciples' claims, the report of the guards is not credible. Stones were rolled away so graves could be robbed (Char. Chaer. 3.3.1), but not with guards posted (at least, not unless the robbers had subdued the guards, normally fatally). Moreover, whereas tomb robbers normally carried off wealth, carrying off the body was so rare that it would shock those who heard of it (Char. Chaer. 3.3).
If the disciples did not protect Jesus while he was alive, surely they would not have risked their lives to rob his tomb after his death (grave robbing was a capital offense--for example, SEG 8.13). Nor could they have rolled away the massive stone without waking the guards. Penalties for falling asleep on guard duty could be severe, and guards who claimed to have slept through the stealing of the body, yet suffered no harm, would sound very suspicious. (Thus, for example, a soldier assigned to guard corpses hanging on crosses to prevent burial found a body stolen and preferred suicide to court-martial and execution--Petr. Sat. 112.) Under normal circumstances, people might suppose that such guards and those who failed to punish them had collaborated in the disappearance of the body, but in this situation those who failed to punish the guards had too much to lose.
It might be argued that someone took the body but guards were not actually present. But then why would the establishment circulate a rumor that guards were present, which would weaken rather than strengthen their case? The testimony of guards who slept through the theft would be less credible than the guesses of investigators after a theft. The story makes the most sense if guards had been present but somehow failed to protect the body, and the officials had to strike a deal to cover their embarrassment.
The narrative's irony announces both God's power and human weakness. Guards who saw an angel were ready, like Judas (26:15), to betray the truth for money (28:12); like Peter (26:69-75), they were ready to deny the unbelievable to protect their lives (28:14). Yet the guards only pretended to have slept through the Messiah's deliverance (28:15), whereas when Jesus needed his disciples the most, they slept through his time of testing (26:40-45). Disciples and enemies alike proved weak, but Jesus' resurrection was an act of God's power.