V.1-2 Some of the Corinthians were asking if he really had the power and authority from God which he was claiming. He tells them that they themselves, having been saved through his preaching, were proof that he was a special Apostle from God.
V.4-6 He had the right to marry like any other person. But he had willingly given up that right for the Lord’s sake. Possibly he was thinking of chap. 7:33.
V.7-23 The Old Testament scriptures taught that when an ox was working, it should not be muzzled (Deut. 25:44Thou shalt not muzzle the ox when he treadeth out the corn. (Deuteronomy 25:4)). In our verse and 1 Timothy 5:18, God is teaching us that those who spend their full time preaching the gospel should be supported by those who have accepted the Lord Jesus. Paul, however, would not accept anything from the Corinthian assembly, because they were acting so badly.
V.18 Paul would not use the right he had to accept money from them so that the gospel would not cost them anything.
V.19 None of the other apostles had sent him out to preach. But he takes a lower place than they all.
V.20-23 He wasn’t trying to make people into Jews, he wanted them to turn to the Lord Jesus. He put himself to no end of trouble to win them to Christ.
V.24-27 Athletes give up all kinds of things while they are in training. Their aim is to win the prize. Their prizes fade away and perish, but the rewards which a believer wins are incorruptible, they can never fade.