What Does 1 Corinthians 5:12 Mean?

For what have I to do to judge them also that are without?—the rhetorical question expects a negative answer: "Nothing!" Krinō (κρίνω, "judge") here means rendering moral verdicts and exercising discipline. Them that are without (τοὺς ἔξω) refers to those outside the church, unbelievers. Paul isn't called to police the morality of pagan Corinth—that's God's prerogative. The church's jurisdiction is internal, not external. Do not ye judge them that are within?—another rhetorical question expecting "Yes!"

Esō (ἔσω, "within") are church members who have covenanted together under Christ's lordship and submitted to mutual accountability. The church is responsible to exercise discernment and discipline within its own ranks. This principle protects against two errors: (1) ignoring sin among believers while condemning the world (hypocrisy), and (2) crusading to impose Christian standards on unbelievers through force (theocracy or moralism). The church's witness is maintained by internal holiness, not external coercion. We evangelize the world with grace while maintaining accountability within the covenant community.