John Chrysostom

"For if in anything I have gloried to him on your behalf." It is high praise when the teacher boasted, for he saith, "I was not put to shame." I therefore rejoiced, because ye showed yourselves to be amended and proved my words by your deeds. So that the honor accruing to me was twofold; first, in that ye had made progress; next, in that I was not found to fall short of the truth. "But as we spake always to you in truth, so our glorying also which I made before Titus was found to be truth." Here he alludes to something further. …

Homily 16 on 2 Corinthians ↗

Theophylact of Ohrid

I, he says, rejoiced at this, that Titus found you to be such as I had described you to him in words. And he himself was comforted when he found you to be such and encountered nothing rude or unpleasant from you. And the fact that Paul boasts about his disciples shows that they were virtuous and that he was loving toward his children. Such should disciples and teachers be even now. …

Commentary on 2 Corinthians ↗

Thomas Aquinas

He assigns the reason for this joy from two aspects: one is on the part of the Apostle, namely, because he was found to be truthful. For the Apostle had commended the Corinthians to Titus before he went to them. But now, because Titus found them to be just as the Apostle had said, he rejoiced that his words were true. And this is what he says, for if I have expressed to him some pride in you, by commending you, I was not put to shame, i.e., I do not blush as having said something false. …

Commentary on 2 Corinthians ↗