7 What then is that which I said, “Is heard with peril if it be not understood”? Many overcome by carnal and damnable lusts, commit all sorts of crimes and impurities, and wallow in such abominable uncleanness, as it is a shame even to mention; and say to themselves these words of the Apostle. See what the Apostle has said, “So that we cannot do the things that you would.” I would not do them, I am forced, I am compelled, I am overcome, “I do the things that I would not,” as the Apostle says. “The flesh lusts against the Spirit, and the Spirit against the flesh, so that you cannot do the things that you would.” You see with what peril this is heard, if it be not understood. You see how it concerns the pastor's office, to open the closed fountains, and to minister to the thirsty sheep the pure, harmless water.
Source: Sermons on Selected Lessons of the New Testament (New Advent)