1 Corinthians 1:1 — Commentary on 1 Corinthians
This epistle is divided into two parts: in the first he sends his greeting and in the other his message (v. 4). As to the first he does three things: first, he mentions the persons who send the greeting; secondly, the persons greeted (v. 2); thirdly, he wishes them well (v. 3). As to the first he mentions the principal person first and describes him from his name, Paul. Enough had been said about this name in the epistle to the Romans. Suffice it to say here that this name is mentioned as a token of humility, for Paul means a small amount, which pertains to humility: "Though you are little in your own eyes, are you not the head of the tribes of Israel?" (1 Sam 15:17); "You have hidden these things from the wise and understanding are revealed them to babes" (Matt 11:25). Then he describes himself from his dignity. First, he mentions how a dignity should be obtained when he says, called, since it is stated in Heb (5:4): "One does not take the honor upon himself, but is called by God, as Aaron was." Secondly, he mentions his dignity, saying: an apostle of Jesus Christ. This, of course, is the highest dignity in the Church and means "sent," because they were sent by God to act in His name on earth; hence it says in Lk (6:13): "He chose from them twelve, whom he named apostles," and below (12:28): "God has appointed in the church, first, apostles." Thirdly, he indicates the source and cause of this dignity when he says: by the will of God. This refers to the will of His good pleasure, which chooses those who rule the Church in one way or another: "The government of the earth is in the hands of the Lord, and over it he will raise up the right man for the time." (Sir 10:4). But when God sets someone in authority on account of the sins of the subjects: "He makes a man that is a hypocrite to reign for the sins of the people" (Jb 34:30), such a ruler is not according to God's will but according to His indignation: "I have given you kings in my anger, and I have taken them away in my wrath" (Hos 13:10). Secondly, he mentions the other person who sends the greeting when he says, and Sosthenes, our brother, whom he mentions along with himself, because he was the one who had reported to the Apostle the quarrels and other failings current among the Corinthians. He calls him brother, to show that he had done this not out of hatred but out of the zeal of charity: "Reprove a wise man and he will love you" (Pr 9:8).
1 Corinthians 1:2 — Commentary on 1 Corinthians
Then he mentions the persons he is greeting, saying: to the church of God that is at Corinth. First, he mentions the chief persons, whom he describes in three ways: first, from their region when he says, to the church of God that is at Corinth, i.e., Christ's faithful assembled at Corinth: "I will thank thee in the great congregation" (Ps 35:18). Secondly, from their gift of grace when he says: to those sanctified in Christ Jesus, i.e., in the faith, passion and sacraments of Christ Jesus: "You were washed, you have been sanctified" (1 Cor 6:11); "Jesus also suffered outside the gate in order to sanctify the people" (Heb 13:12). Thirdly, he mentions the source of grace when he says: called to be saints, because they arrived at sanctity through the grace of being called: "Those whom he predestined he also called" (Rom 8:30); "He called you out of darkness into his marvelous light (1 Pt 2:9). Then he mentions the other persons, namely the faithful who were not in that city but lived in the diocese of the city or in the environs; hence he says: together with those who call on the name of our Lord Jesus Christ by confessing the true faith: "All who call upon the name of the Lord shall be delivered" (Jl 2:32). And this in every place subject to their jurisdiction; both their Lord and ours, because their subjection to the bishop of the city did not exempt them from the Apostle's power; rather they were more subject to the Apostle than to those whom he had subjected them: "In all places of his dominion, bless the Lord, O my soul!" (Ps 103:22).