We know, not only from the Bible, but also from other early writings that Christianity spread far and wide throughout the 1st Century. This is so well known as to be beyond dispute.
Jesus was crucified when Pontius Pilate was governor of Judea. Not only the NT but Tacitus, the Roman historian who despised Christianity, makes reference to this in the late 1st Century.
The tomb was guarded. A standard Roman guard unit consisted of sixteen crack troops with four on duty while twelve would be sleeping. A rota of four fresh troops after four hours would take their place. The ones resting would lie on the ground in front of the active guard unit. In Acts 12:4 we see Herod's guard unit (patterned after the Roman model) consisting of four squads of four soldiers each.
On the third day the tomb was empty and many claimed to have seen Him for a forty-day period; at the end of which He ascended into heaven.
- The disciples stole the body while the guards were sleeping and pretended He was alive.
Problem: No motive (they were defeated and discouraged). No means ( Roman guard units were highly disciplined fighting units). No later recantations; even though most suffered tortuous deaths.
Problem: With this logic we would also assume that He somehow rolled aside a 2.5 ton stone and convinced people He was raised from the dead. However, the Romans knew how to kill a man and they made sure their victims were dead when they took them off the cross. Furthermore, the standard burial practices of wrapping the body in cloth with spices would probably suffocate a healthy person, let alone a severely wounded one.
Problem: When Peter preached in Jerusalem on the day of Pentecost, all the priests had to do was to produce the body. They didn't, because they themselves didn't know where He was.
Problem: To continue this thought, they looked into an empty tomb and falsely concluded that He had risen from the dead. Apparently, the disciples, the soldiers and the priests all forgot where the tomb was (even though it belonged to a prominent member of the Sanhedrin, Joseph of Arimathea).
Problem: The varied times of day, the different personalities involved, the different geographical locations and the fact that all appearances stopped after the 40-day period make this virtually impossible. Furthermore, the body would still be in the tomb and the authorities could simply show it to the multitudes.
(Excerpted from 'Origins and Redemption' by Dr. Frank Humphrey)