Theophylact of Ohrid, on 2Cor 1:1

“Paul, an apostle of Jesus Christ by the will of God, and Timothy our brother: to the church of God that is at Corinth, with all the saints that are in all Achaia:”

“Since the apostle, in his first epistle, sent Timothy to Corinth and then received him back again when he returned, he rightly joins his name to his own. Moreover, Timothy had shown the Corinthians proof of his virtue as well. Thus, the apostle mentions Timothy in the present epistle as a person already known to the Corinthians and who had corrected many things among them. Notice that sometimes he calls him a son: "as a son with a father," he says, "he served with me in the gospel" (Phil. 2:22), sometimes a fellow worker: "for he does the work of the Lord, as I also do" (1 Cor. 16:10), and now a brother, presenting him as worthy of respect in every regard. Again he unites them, having said "church"; for those who are in division do not constitute a church. He mentions all those living in Achaia, showing preference to the Corinthians by greeting everyone through the epistle addressed to them, and at the same time calling the whole people to concord. Moreover, since they were all wavering, he offers them a common remedy; he does the same thing in the epistles to the Galatians and to the Hebrews. And by calling them saints, he shows that if anyone is impure, he is unworthy of this greeting and designation.”

Imported from an open dataset — not yet checked against the printed edition.