Matthew tells us the story like this:

Early on Sunday morning, as the new day was dawning, Mary Magdalene and the other Mary went out to visit the tomb. Suddenly there was a great earthquake! For an angel of the Lord came down from heaven, rolled aside the stone, and sat on it. His face shone like lightning, and his clothing was as white as snow. The guards shook with fear when they saw him, and they fell into a dead faint. Then the angel spoke to the women. Dont be afraid! he said. I know you are looking for Jesus, who was crucified. He isnt here! He is risen from the dead, just as he said would happen. Come, see where his body was lying. And now, go quickly and tell his disciples that he has risen from the dead, and he is going ahead of you to Galilee. You will see him there. Remember what I have told you. [Matthew 28:1-7. NLT]
The Christian story is founded on an empty tomb and the resurrection of Jesus Christ. If the tomb was not empty, then the Christian movement would have been snuffed out just by someone going and getting the body of Jesus.

There are four main theories to explain how the tomb became empty.

1. Firstly, maybe the Jewish or Roman authorities stole Jesus’ body, and the disciples mistakenly assumed he had been raised, inventing stories of appearances afterwards. The reason that this is so clearly wrong is that the authorities were trying to stop the Christian movement from growing, and if they had stolen his body they would simply have produced it.

2. Secondly, maybe Jesus did not really die, but fell into some sort of unconscious state, then revived in the tomb, and moved the stone himself. This is even more ridiculous, if you know anything about Roman crucifixion. Soldiers executed hundreds of people a year, they knew exactly what they were doing, and one could survive it, far less roll away a two-ton stone and then take out two guards.

3. Thirdly, maybe the disciples stole the body and then imagined or pretended they had seen him alive afterwards. But consider the high improbability of multiple near-identical hallucinations that would have been needed and the fact that many of the witnesses were tortured and killed for their proclamation of Jesus’ resurrection, which you would be unlikely to undergo if you had made it up.

4. This only leaves option four – that God really did raise Jesus from the dead.

From the earliest days until now, the resurrection has been central to Christian belief and practice. In fact, it is the cornerstone of the Christian faith and its strongest evidence (1 Cor.15:14).

Let's worship the risen Christ today – Jesus, Lord of all and soon coming King.

P.S. For some excellent detailed evidence for the resurrection of Jesus, I recommend these two books:

The Resurrection of the Son of God by N.T. Wright

The Case for Christ: A Journalist's Personal Investigation of the Evidence for Jesus by Lee Strobel