John Chrysostom

"For He that wrought for Peter unto the Apostleship of the Circumcision wrought for me also unto the Gentiles." He calls the Gentiles the Uncircumcision and the Jews the Circumcision, and declares his own rank to be equal to that of the Apostles; and, by comparing himself with their Leader not with the others, he shows that the dignity of each was the same. …

Homily on Galatians 2 ↗

Theophylact of Ohrid

Here he also shows himself equal to Peter. For He who entrusted to Peter the work of preaching the gospel to the Hebrews gave the same to me for the Gentiles. And notice how he showed that his preaching was not only pleasing to the apostles, but was also acceptable to God. For concerning the apostles he says that they "recognized the grace." He did not say "heard," but from the very deeds themselves "recognized." For how would God have given me this gift if such preaching were displeasing to Him?

Commentary on Galatians ↗

Oecumenius

[PHOTIUS] "just as Peter." If Paul said that those around Peter practice circumcision for reasons of convenience, he would seem even to allow this himself, and therefore by cooperating all the more he would have been shown to be for those with whom he had a quarrel. He says, For if Peter does well by permitting it, why should you not as well? And why do you bitterly reproach what you call stewardship? Let it act and do not rebuke, and call it whatever is dear to you, whether stewardship, or doctrine and exactness. …

Commentary on Galatians ↗

Thomas Aquinas

But because someone might say: What evidence have you that the commission to preach the Gospel to the Gentiles was given you, he interjects that it was through certain works of Christ. For just as it is evident that Peter received the Gospel from Christ because of the marvels Christ wrought through him, so it is evident that I received it because of the miracles Christ worked and does work in me. …

Commentary on Galatians ↗