1 Corinthians 1:1 - Wesley's Explanatory Notes

Paul, called to be an apostle — There is great propriety in every clause of the salutation, particularly in this, as there were some in the church of Corinth who called the authority of his mission in question. Through the will of God — Called "the commandment of God," 1 Timothy 1:1 This was to the churches the ground of his authority; to Paul himself, of an humble and ready mind. By the mention of God, the authority of man is excluded, Galatians 1:1; by the mention of the will of God, the merit of Paul, 1 Corinthians 15:8, &c. And Sosthenes — A Corinthian, St. Paul's companion in travel. It was both humility and prudence in the apostle, thus to join his name with his own, in an epistle wherein he was to reprove so many irregularities. Sosthenes the brother — Probably this word is emphatical; as if he had said, Who, from a Jewish opposer of the gospel, became a faithful brother.