Charles Ellicott Commentary 1 Corinthians 5:11

"but as it is, I wrote unto you not to keep company, if any man that is named a brother be a fornicator, or covetous, or an idolater, or a reviler, or a drunkard, or an extortioner; with such a one no, not to eat." — 1 Corinthians 5:11 (ASV)

But now I have written to you... —that is, “But what I meant was” that you were not to associate with a Christian guilty of these things. It may seem strange that the word “idolater” should be included in this category; for in what sense could a “brother” be a worshipper of idols? It is probable that the word “idolater” involves the idea, not merely of worshipping an image, but of the sensuality that accompanied various forms of heathen worship, and of which evidently some of the Corinthian brethren were partakers. (See Ephesians 5:5 and Colossians 3:5, where “idolatry” is identified with a vice related to lasciviousness.)