Blessed Paul, in the work of his ministry, not only met with opposition from those without, but discouragement from those within. He was under reproach; false brethren questioned his apostleship, and were very industrious to lessen his character and sink his reputation; particularly here at Corinth, a place to which he had been instrumental in doing much good, and from which he had deserved well; and yet there were those among them who upon these heads created him great uneasiness. Note, It is no strange nor new thing for a minister to meet with very unkind returns for great good-will to a people, and diligent and successful services among them. Some among the Corinthians questioned, if they did not disown, his apostolical character. To their cavils he here answers, and in such a manner as to set forth himself as a remarkable example of that self-denial, for the good of others, which he had been recommending in the former chapter. And, 1. He asserts his apostolical mission and character: Am I not an apostle? Have I not seen Jesus Christ our Lord? To be a witness of his resurrection was one great branch of the apostolical charge. "Now," says Paul, "have not I seen the Lord, though not immediately after his resurrection, yet since his ascent?" See Co1 4:8. "Am I not free? Have I not the same commission, and charge, and powers, with the other apostles? What respect, or honour, or subsistence, can they challenge, which I am not at liberty to demand as well as they?" It was not because he had no right to live of the gospel that he maintained himself with his own hands, but for other reasons. 2. He offers the success of his ministry among them, and the good he had done to them, as a proof of his apostleship: "Are not you my work in the Lord? Through the blessing of Christ on my labours, have not I raised a church among you? The seal of my apostleship are you in the Lord. Your conversion by my means is a confirmation from God of my mission." Note, The ministers of Christ should not think it strange to be put upon the proof of their ministry by some who have had experimental evidence of the power of it and the presence of God with it. 3. He justly upbraids the Corinthians with their disrespect: "Doubtless, if I am not an apostle to others, I am so to you, Co1 9:2. I have laboured so long, and with so much success, among you, that you, above all others, should own and honour my character, and not call it in question." Note, It is no new thing for faithful ministers to meet with the worst treatment where they might expect the best. This church at Corinth had as much reason to believe, and as little reason to question, his apostolical mission, as any; they had as much reason, perhaps more than any church, to pay him respect. He had been instrumental in bringing them to the knowledge and faith of Christ; he laboured long among them, nearly two years, and he laboured to good purpose, God having much people among them. See Act 18:10, Act 18:11. It was aggravated ingratitude for this people to call in question his authority.