John Chrysostom

"Nevertheless He that comforteth the lowly comforted us by the coming of Titus." For since he had testified great things of them in what he said, that he may not seem to be flattering them he cites as witness Titus the brother, who had come from them to Paul after the first Epistle to declare unto him the particulars of their amendment. But consider, I pray you, how in every place he maketh a great matter of the coming of Titus. …

Homily 14 on 2 Corinthians ↗

Theophylact of Ohrid

Since he said much in praise of the Corinthians, he brings Titus as a witness. Who then "comforts the downcast"? God, he says. He also comforted us by sending us Titus; for his arrival was sufficient to dispel our sorrow. He also wishes to present this man to them as worthy of respect, which is why he ascribes great significance to his arrival.

Commentary on 2 Corinthians ↗

Thomas Aquinas

Then when he says, But God, who comforts, he states the reason for his consolation, which he applauds from two aspects, namely, from the gratifying presence of Titus and from the consolation of Titus (v. 7). He says therefore: although we were gravely afflicted here, God, who comforts the downcast, comforted us by the coming of Titus, whose presence was very pleasing and a great help to me: "Who comforts us in all our affliction" (2 Cor. 1:4). …

Commentary on 2 Corinthians ↗