John Chrysostom

"Wherefore? because I love you not? God knoweth." Quickly [is it done], and by an easy method. But still, not even so did he rid them of those charges. For he neither said, "ye are not weak," nor yet, "ye are strong;" but, "I love you," which very greatly aggravated the accusation against them. For the not receiving from them, because they felt it an exceeding grievance, was a proof of special love toward them. …

Homily 23 on 2 Corinthians ↗

Theophylact of Ohrid

Intending to explain the reason why he did not take from them, namely, because of the appearance of false apostles, he thereby undermines the Corinthians' suspicion: you do not take, as it seems, out of hatred toward us. Therefore he also says: I love you more and do not wish to offend you, because you are easily led astray. But he does not say this so clearly, so as not to shame their weakness, and turns his speech to another reason.

Commentary on 2 Corinthians ↗

Thomas Aquinas

Then when he says, And why?, he presents the cause why he did not take payment from them. First, he excludes the false cause; secondly, he gives the true one (v. 12). In regard to the first it should be noted that the false apostles charged the Apostle with not taking payment from the Corinthians, because he did not love them and because he did not intend to help and serve them. He says therefore: Why do I do this? Because I do not love you?, i.e., is it from any hatred I bear towards you, as the false apostles claim? …

Commentary on 2 Corinthians ↗