Simon Greenleaf was a Harvard law professor in the 1800’s who was an expert in the law of evidence. Simon applied the rule of law to the 4 gospels to see if they could stand up under legal scrutiny. After an exhaustive investigation of the Bible, as well as other ancient documents, he came to the conclusion that the gospels were credible.
The overwhelming piece of evidence for Greenleaf, was the death of the Apostles. The Romans had always held the position that the disciples had stolen the body, even though it was guarded by Roman soldiers.
About 30 years after the resurrection, the Christian religion was becoming a problem for the Roman government. In an attempt to discredit Christianity, they offered the disciples a deal. Confess that they stole the body or die a horrible death. They all chose the latter.
If the disciples had stolen the body, they would have known the resurrection was false and not worth dying for.