Theophylact of Ohrid, on 1Thess 1:1

“Paul and Sylvanus and Timothy: to the church of the Thessalonians, in God the Father, and in the Lord Jesus Christ.”

“The Apostle Paul in his letter to the Thessalonians places Timothy alongside himself. Meanwhile, in the Epistle to the Ephesians he does not do this, even though Timothy was known to them. It seems to me this is because he intended to send him to the Ephesians immediately, which is why it was unnecessary to write the epistle on behalf of someone who was to deliver it. But here the situation is different: Timothy had recently returned from Thessalonica, so he rightly places him alongside himself. But before Timothy he places Silvanus, probably because Timothy himself, out of humility, requested this, imitating his teacher Paul, who includes his disciples alongside himself. Here Paul does not call himself either an apostle or a servant, as he usually does in other epistles, because the Thessalonians were newly converted and had not yet come to know him closely. Therefore, it was not fitting to remind them of his dignity. Though the Thessalonians were few in number and had not yet been closely united among themselves, he nevertheless calls them a church, encouraging them by the very name itself: since the name "church" for the most part signifies a multitude. Since there were both Greek and Jewish churches, he, distinguishing this church from those, says, which is "in God the Father." It is a great dignity to be "in God." For if someone is a slave of sin, he is not "in God." Note: the preposition "in" (εν) applies both to the Father and to the Son. He wishes for them that more and more they would advance in the gifts of God, but would also have peace, not being prideful before one another.”

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