10 not at all meaning the immoral of this world, or the greedy and robbers, or idolaters, since you would then need to go out of the world. 11 But now I am writing to you not to associate with anyone who bears the name of brother or sister who is sexually immoral or greedy, or is an idolater, reviler, drunkard, or robber. Do not even eat with such a one. 12 For what have I to do with judging those outside? Is it not those who are inside that you are to judge?
Matthew Henry's Commentary on 1 Corinthians 5:10-12
Commentary on 1 Corinthians 5:9-13
(Read 1 Corinthians 5:9-13)
Christians are to avoid familiar converse with all who disgrace the Christian name. Such are only fit companions for their brethren in sin, and to such company they should be left, whenever it is possible to do so. Alas, that there are many called Christians, whose conversation is more dangerous than that of heathens!