Albert Barnes Commentary 1 Corinthians 15:5

"and that he appeared to Cephas; then to the twelve;" — 1 Corinthians 15:5 (ASV)

And that he was seen of Cephas. This refers to Peter. See the notes on John 1:42.

The resurrection of Christ was a fact to be proved, like all other facts, by competent and credible witnesses. Paul, therefore, appeals to the witnesses who had attested, or who still lived to attest, the truth of the resurrection of the Lord Jesus, and he shows that it was not possible that so many witnesses should have been deceived.

As this was not the first time that the evidence had been stated to them, and as his purpose was merely to remind them of what they had heard and believed, he does not present all the witnesses to the event but refers only to the more important ones.

He does not, therefore, mention the woman to whom the Saviour first appeared, nor does he refer to all the times when the Lord Jesus manifested himself to his disciples.

However, he does not refer to them merely in general, but mentions names and refers to persons who were alive at that time, who could attest to the truth of the resurrection.

It may also be observed that Paul probably follows the exact order in which the Lord Jesus appeared to the disciples, though he does not mention all the instances. For an account of the persons to whom the Lord Jesus appeared after his resurrection, and the order in which this happened, see the Harmony at the end of the Notes on Matthew.

Then of the twelve. This refers to the apostles, who were still called "the twelve," even though Judas was not one of them. It was common to call the apostles "the twelve."

Jesus appeared to the apostles at one time in the absence of Thomas (John 20:19, 24) and also to them when Thomas was present (John 20:24–29). Paul probably refers here to the latter occasion, when all the surviving apostles were present.