They that were of the circumcision - Christians who had been converted from among the Jews.
Contended with him - Disputed; reproved him; charged him with being in fault. This is one of the circumstances which show conclusively that the apostles and early Christians did not regard Peter as having any particular supremacy over the church, or as being in any special sense the vicar of Christ upon earth. If he had been regarded as having the authority which the Roman Catholics claim for him, they would have submitted at once to what he had thought proper to do. But the earliest Christians had no such idea of Peter’s so-called authority. This claim for Peter is not only opposed to this place, but to every part of the New Testament.