That ye sorrowed after a godly sort. — Better, as before, that ye sorrowed after the will of God. The series of emotional words that follow represent the Apostle’s estimate of what he had heard from Titus. There was (1) earnestness where there had been indifference to evil, or even approval of it (1 Corinthians 5:2); and this was shown (2) in the vindication of their conduct which they had sent through Titus, and (3) in their stern “indignation” against the offender; (4) in their “fear,” partly of the supernatural chastisement which St. Paul had threatened, partly of the judgment of God, which was against such things; (5) in the longing to have him once more among them which mingled with their fear; (6) in their new “zeal” for the law of purity; (7) in their actual vengeance, i.e., their sentence of condemnation passed upon the offender.
To be clear in this matter. — Literally, in the matter, possibly with exclusive reference to the sin condemned in 1 Corinthians 5:1-5, but possibly also, as in 1 Thessalonians 4:6, as an euphemistic expression for the sin of impurity generally.