What does 1 Corinthians 16:20 mean?

In concluding his letter to the Corinthians, Paul has sent greetings from the churches in Asia, as well as from Aquila and Prisca, former Corinthians and his fellow workers in tent-making and ministry. Now he sends more general greetings from "all the brothers." By this, Paul likely means all the other believers in Ephesus and, perhaps, in the world generally. Paul may once again be emphasizing that the Corinthians are just one church among a growing number of churches in the world.

As he does in the conclusion to other letters, he tells his readers to greet each other with a holy kiss (1 Thessalonians 5:26; Romans 16:16; 2 Corinthians 13:12). A quick kiss on one or both cheeks has been a common greeting between friends in many cultures down through history. Early Christians formalized this kiss of greeting as a "holy" expression of the family bond between believers in Jesus. It is difficult—though possible—to maintain resentment between believers when they must kiss each other in greeting, at least without making it clear one is being dishonest. Such a kiss would at least represent their unity, mutual forgiveness, and inclusion in the "set apart" community of Christians.