What does 2 Corinthians 13:12 mean?

This passage closes Paul's message to the church in Corinth with two features found at the end of many of his letters: a warm, gracious tone and a series of brief commands and reminders.

Paul now tells them to greet each other with a "holy kiss." In that era, a quick kiss on either one or both cheeks was a common greeting between friends and family. In some cultures, even in the modern world, brief kisses on the cheeks are still used as a friendly, non-romantic greeting. Early Christians formalized this style of greeting as a "holy" expression of the family bond between believers in Jesus. Paul regularly encouraged the practice (1 Thessalonians 5:26; Romans 16:16; 1 Corinthians 16:20).

In part, perhaps, Paul felt that the "holy kiss" would promote unity between the Corinthians. It must be more difficult to stay resentful and divided from other believers while regularly using a "family" style of greeting. Such kisses would, at the least, give a physical expression to their needed unity, mutual encouragement, and forgiveness.