Now when the Sabbath was past, Mary Magdalene, Mary the mother of James, and Salome brought spices, that they might anoint Him. Very early in the morning, on the first day of the week, they came to the tomb when the sun had risen. And they said among themselves, "Who will roll away the stone from the door of the tomb for us?" But when they looked up, they saw that the stone had been rolled away - for it was very large. And entering the tomb, they saw a young man clothed in a long white robe sitting on the right side; and they were alarmed. But he said to them, "Do not be alarmed. You seek Jesus of Nazareth, who was crucified. He is risen! Here is not here. See the place where they laid him. But go and tell his Disciples - and Peter - that he is going before you into Galilee; there you will see Him, as He said to you." And they went out quickly and fled from the tomb, for they trembled and were amazed. And they said nothing to anyone, for they were afraid.
In Biblical times the weight that the testimony of women was given was half that of a man. If Christianity were an invented religion, then it would be a source of embarrassment to the early Church that women were the first witnesses. Why not Peter? Why not have Jesus appear to all of his enemies and strike them dead, like something out of a Hollywood movie?
Within a few weeks the disciples - the same ones who could not run away from Jesus fast enough - were proclaiming the fact of His Resurrection. One by one they died for their faith. Some, like Stephen, were stoned to death. Peter was crucified upside down! Only John apparently avoided execution, and he spent time on the island of Patmos in exile.
Only one thing could have brought about this change: the fact that Jesus was raised from the dead and they saw Him alive.