12 What business is it of mine to judge those outside the church? Are you not to judge those inside?
12 For what have I to do to judge them also that are without? do not ye judge them that are within?
12 For what have I to do with judging outsiders? Is it not those inside the church whom you are to judge?
12 I'm not responsible for what the outsiders do, but don't we have some responsibility for those within our community of believers?
12 For what have I to do with judging those also who are outside? Do you not judge those who are inside?
12 It isn't my responsibility to judge outsiders, but it certainly is your responsibility to judge those inside the church who are sinning.
Matthew Henry's Commentary on 1 Corinthians 5:12
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!