2 Peter 1:1

The apostle Peter, being moved by the Holy Ghost to write once more to those who from among the Jews were turned to faith in Christ, begins this second epistle with an introduction, wherein the same persons are described and the same blessings are desired that are in the preface to his former letter; but there are some additions or alterations which ought to be taken notice of, in all the three parts of the introduction. I. We have here a description of the person who wrote the epistle, by the name of Simon, as well as Peter, and by the title of servant, as well as that of apostle. Peter, being in both epistles, seems to be the name most frequently used, and with which he may be thought to be best pleased, it being given him by our Lord, upon his confessing Jesus to be Christ the Son of the living God, and the very name signifying and sealing that truth to be the fundamental article, the rock on which all must build; but the name Simon, though omitted in the former epistle, is mentioned in this, lest the total omission of that name, which was given him when he was circumcised, should make the Jewish believers, who were all zealous of the law, to become jealous of the apostle, as if he disclaimed and despised circumcision.

— Matthew Henry's Concise Commentary (public domain)