John Chrysostom

"For if he that cometh preacheth another Jesus whom we did not preach:" showing hereby that their deceivers were not Corinthians, but persons from some other quarter previously corrupted: wherefore he saith, "he that cometh." "If ye receive a different Spirit, if a different Gospel which ye did not accept, ye do well to bear" with him. What sayest thou? Thou that saidst to the Galatians, "If any preach another Gospel to you than that ye have received, let him be anathema;" dost thou now say, "ye do well to bear" with him? …

Homily 23 on 2 Corinthians ↗

Theophylact of Ohrid

What are you saying, Paul? In the Epistle to the Galatians you wrote: if anyone preaches to you a gospel other than what you have received, let him be anathema (Gal. 1:8); so how can you now say that if they preached another Jesus, your forbearance would be justified? Listen, then: the false apostles boasted that they brought more than the true apostles. …

Commentary on 2 Corinthians ↗

Thomas Aquinas

Having described the zeal he had for the Corinthians and proved it reasonable, the Apostle now rejects their excuse. In regard to this he does two things. First, he proposes their excuse; secondly, he removes it (v. 5). In regard to the first it should be noted that the Corinthians might suppose that he has zeal for them, because he feared that they might set aside his teaching on account of the false apostles' teaching; hence they could say: it is obvious that lesser goods should be discarded in favor of greater goods. …

Commentary on 2 Corinthians ↗