Matthew 28:11-15

Mat 28:11 (KJB)
Now when they were going, behold, some of the watch came into the city, and showed unto the chief priests all the things that were done.

While the women were departing from the meeting with Jesus, some of those soldiers who were part of the tomb watch had come into the city and went to the chief priests and told them about the empty tomb and the earthquake and the other events they witnessed which caused them to be like dead men. Instead of going directly to their commanding officer, they went to the chief priests. They did this because they may have been put to death by being accused of sleeping on the job which was a capital offense in the Roman army. It seems the story of the empty tomb had started spreading much more rapidly than the fact of the resurrection. Something we learn in life is that truth moves much more slowly than lies but its reports are very dependable. I am sure that the chief priests were now fearing had happened what they hoped would not and that is the disciple came and took the body and now they will proclaim His resurrection.

Mat 28:12 (KJB)
And when they were assembled with the elders, and had taken counsel, they gave large money unto the soldiers,

Now the chief priests and the elders had now met to discuss the situation because they knew that soon the story of the resurrection would start circulating among the people. They needed to do something in a hurry to try and quash that rumor before it becomes a stable teaching among the people. So their answer to the problem was bribery. They had decided to give the soldiers a big amount of money for the purpose of creating a lie so they could suppress the story.

Mat 28:13 (KJB)
Saying, Say ye, His disciples came by night, and stole him away while we slept.

The story which they had asked the soldiers to tell was literally their death sentence. They asked the soldiers to tell people that they fell asleep on duty and that just as they predicted the disciples came by night and stole the body from the tomb. If Pilate had heard about this story without knowing the particulars, then he would have immediately ordered the execution of those soldiers for dereliction of duty. This story has two questions which needed to be answered. First, if the soldiers were asleep then how would they know the disciples came and stole the body and not somebody else and secondly, if you were not asleep, then why did you not fight those who were trying to steal the body?

Mat 28:14 (KJB)
And if this come to the governor's ears, we will persuade him, and secure you.

The soldiers had known that the Jewish leaders had influence with Pilate and if he heard of this story than they were sure that the leaders would straighten out all of the problems. The Sanhedrin had promised them that they would take care of the entire situation and that their lives would be safe.

Mat 28:15 (KJB)
So they took the money, and did as they were taught: and this saying is commonly reported among the Jews until this day.

So then the soldiers had taken the money and agreed to stick to the story that the disciples came by night and stole the body. They now had the full backing of the Jewish authorities and the story was propagated. Not only in the time when Matthew penned this Gospel around 50 A.D., according to Justin Martyr who lived in the second century, the lie was very well implanted all over the place and was the standard belief about the disappearance of the body of Jesus. Even in 2012, a man in Israel claimed he found the bones of Jesus meaning that Jesus did not rise from the dead nor ascend into Heaven. The lies continue 2,000 years later.