1 Corinthians 15:1-8
1Moreover, brethren, I declare unto you the gospel which I preached unto you, which also ye have received, and wherein ye stand; 2By which also ye are saved, if ye keep in memory what I preached unto you, unless ye have believed in vain. 3For I delivered unto you first of all that which I also received, how that Christ died for our sins according to the scriptures; 4And that he was buried, and that he rose again the third day according to the scriptures: 5And that he was seen of Cephas, then of the twelve: 6After that, he was seen of above five hundred brethren at once; of whom the greater part remain unto this present, but some are fallen asleep. 7After that, he was seen of James; then of all the apostles. 8And last of all he was seen of me also, as of one born out of due time.
Comment: Paul passes on the testimony of the early Christian community asserting the death and resurrection of Jesus and listing several groups of eyewitnesses. The eyewitnesses are listed in order of the appearances and the numbers of people involved; Peter, the 12 apostles, more than 500 followers, James, and all the apostles. Finally, much later, Paul had an encounter with the resurrected Jesus. These statements derive their credibility from the fact that great care has been taken to precisely, in so far as is reasonable; delineate the witnesses involved, the numbers involved, and the order of appearance. Delineating specifics establishes the veracity of Jesus' death and resurrection. In fact, the gospels do this very thing when listing the numbers of people involved in various events [e.g. the feeding of the five thousand in Matthew 14:13-21, Lazarus being dead 4 days before being raised in John 11:17, 153 large fish caught in John 21:11] indicating, through detailed descriptions, the reality of the events being described. Note that more than 500 followers apparently had seen the resurrected Jesus. To use the number 500 implies someone had attempted to count them at some point. Otherwise a more general term along the lines of "a lot of followers had seen Jesus" would have been used. In addition, Paul states that most of these "more than 500 eyewitnesses" were still alive and available for interview even as he wrote this letter to the Corinthians. The fact that most eyewitnesses were still alive when this letter was written indicates a very early date for the belief in Jesus' resurrection. This means the resurrection was not a mythological development. Still, even more credibility is added by Paul when he states that he, too, had seen the resurrected Jesus even though he had persecuted those who believed in Jesus' resurrection. In verse 2, Paul challenges the Corinthian's belief in the resurrection indicating they're only saved if he is alive. If he were still dead, there would be no savior to save them.