1 Cor. 15:3-8 (ESV)
For I delivered to you as of first importance what I also received: that Christ died for our sins in accordance with the Scriptures,  that he was buried, that he was raised on the third day in accordance with the Scriptures,  and that he appeared to Cephas, then to the twelve.  Then he appeared to more than five hundred brothers at one time, most of whom are still alive, though some have fallen asleep.  Then he appeared to James, then to all the apostles.  Last of all, as to one untimely born, he appeared also to me.
Paul reiterates here that the Gospel is of first importance. He then goes on to explicate the gospel. Christ died for our sins in accordance with Scriptures. Of course Paul is here referring to all the prophecies of the Old Testament that were finally completed in Christ. The New Testament wasn’t quite around yet, as 1 Corinthians is one of the first documents of the New Testament to be written, preceding even the gospels. This is perhaps one of the biggest apologetically arguments for the truth, veracity, and distinctiveness of the Christian faith. No other faith begins with prophecies that were recorded as long as 2,000 years before the event. The last prophecy regarding Christ was 400 years old when Christ was born. And Christ fulfilled it. Not in a mythical world, or time, but in our world in our time. His death and resurrection are historical facts. He died for our sins in accordance with the Scriptures. He was buried, and just as the Scriptures told us, he was raised on the third day.
Then Paul adds testimony as evidence of the resurrection. First he appeared to Cephas, then to the twelve. The Testimony of two was enough to convict Christ in court. By the legal rules of the time Paul has already far outweighed the evidence in favor of the resurrection. Then he appeared to more than five hundred, most of whom are still alive. “If you Corinthians don’t believe me, go ask them, they will tell you.” “Then to James, and all the apostles.” James, here, is probably the brother of Christ, bishop of Jerusalem, though we are uncertain if he was the writer of the N.T. book by the same name. All the apostles probably refer to the seventy whom Christ once sent out to preach the kingdom.
The Bible presents the resurrection as fact. Paul presents it as fact, historical fact like any other fact. We can take it or leave it I suppose. But we can’t believe that this was some sort of figurative resurrection. The Bible doesn’t give us that option. It provides witness, and evidence. If today we can’t question the witnesses, they have still left us more testimony than we have for any other historical occurrence of which we do not question. Last of all, Paul says, “He appeared to me.” Paul bases his apostleship on this. He say the risen Christ.
The death and resurrection is of prime importance. People don’t like that today, they would rather make aspects of the law of prime importance. They say things like “the essence of the gospel is imitating Christ.” Paul doesn’t agree. The essence of the gospel that which is of prime importance, is that Christ died for our sins in accordance with Scripture.