The instruction for brethren to greet one another with a kiss appears five times in The New Testament (Romans 16:16; 1 Corinthians 16:20; 2 Corinthians 13:12; 1 Thessalonians 5:26; 1 Peter 5:14). How should we understand this?
Kissing was a common cultural form of greeting. The kiss was generally given on the cheek, forehead, or beard (Zondervan’s Pictorial Dictionary). Such occurred between females (Ruth 1:9), between males (Genesis 27:26-27; 33:4; 45:15; 48:10; 50:1; Exodus 4:27; 18:7; 1 Samuel 20:41; 2 Samuel 14:33; 1 Kings 19:20; Luke 7:45; 15:20; Matthew 26:49), and such occurred between genders (1 Kings 19:20; Lk 7:38). It occurred between relatives (Genesis 27:26-27; 33:4; 45:15), friends (1 Samuel 20:41; 2 Samuel 19:39), and church members (Acts 20:37).
Even today, kissing is a common form of greeting in some countries. Such is very common in southern Europe, eastern Europe, the Mediterranean, the Middle East and Latin America.
There is reason to conclude that this is cultural. The New Testament does not originate the practice. Instead, it appeals to a common existing practice, a common form of greeting.
However, there is a principle that transcends culture. We are to be friendly. Else where, we are told “Greet the friends by name” (3 John 14). Our greetings should be out of genuine love. Peter speaks of “A kiss of love” (1 Peter 5:14). We are to “In sincere love of the brethren, love one another fervently with a pure heart” (1 Peter 1:22) “Let love be without hypocrisy” (Romans 12:9).
Moreover, I believe that The New Testament is cautioning the readers concerning their interaction. It seems to be regulating an existing practice. Robin Haley “Paul did not invent the kiss, but tried to regulate the customary use of it as a greeting to keep it from coming carnal” (A commentary on The Book of Romans, p. 271). Dave Miller, “Paul’s purpose was to regulate the well established custom…Paul attempted to create within early Christians a consciousness of the inherent danger of this social greeting form: lust…Any cultural practice that calls for bodily contact carries this built-in hazard. Christians must be privy to that fact” (Article; Kissing and Culture, Firm Foundation, Sept. 1988)
Some seem to have indeed abused the kiss. Clement of Alexandria wrote in the second century, “Love is not proved by a kiss, but by kindly feeling. But there are those that….make churches resound with a kiss, not having love within…for this very thing, the shameless use of a kiss…occasions foul suspicions and evil reports” (Paedagogus, Book 3, chapter 11). Moreover, consider the worlds of Athenagoras in the second century, “If any one kiss a second time because it gives him pleasure [he sins]…Therefore this kiss, or rather the salvation, should be given the greatest care, since, if there be mixed with it the least defilement of thought, it excludes us from eternal life” (Intercession in behalf of Christians).