But now I write unto you (νυν δε εγραψα υμιν). This is the epistolary aorist referring to this same epistle and not to a previous one as in verse 1. Corinthians 5:9. As it is (when you read it) I did write unto you.

If any man that is named a brother be (εαν τις αδελφος ονομαζομενος η). Condition of the third class, a supposable case.

Or a reviler or a drunkard (η λοιδορος η μεθυσος). Λοιδορος occurs in Euripides as an adjective and in later writings. In N.T. only here and 1. Corinthians 6:10. For the verb see 1. Corinthians 4:12. Μεθυσος is an old Greek word for women and even men (cf. παροινος, of men, 1. Timothy 3:3). In N.T. only here and 1. Corinthians 6:10. Cf. Romans 13:13. Deissmann (Light from the Ancient East, p. 316) gives a list of virtues and vices on counters for Roman games that correspond remarkably with Paul's list of vices here and in 1. Corinthians 6:10. Chrysostom noted that people in his day complained of the bad company given by Paul for revilers and drunkards as being men with more "respectable" vices!

With such a one, no, not to eat (τω τοιουτω μηδε συνεσθιειν). Associative instrumental case of τοιουτω after συνεσθιειν, "not even to eat with such a one." Social contacts with such "a brother" are forbidden