KISS
This common form of greeting between relatives is sanctified by its adoption by the church. Five of the Epistles end with the exhortation to greet one another with a holy kiss, or kiss of love (Rom. 16:16; 1 Cor. 16:20; 2 Cor. 13:12; 1 Thes. 5:26; 1 Peter 5:14).
When Paul said goodbye to the elders of Ephesus, they cried sadly, and embraced him and kissed him. Getting permission to kiss the hand of a superior was an honor. The pagans kissed their gods (1 Kings 19:18; Hos. 13:2).
In the case of distant objects of worship, such as the sun and moon, their worshipers kissed their hands (Jb. 31:26, 27). Hence the most generalized word for worship in the NT is “proskuneõ”, from “kuneõ”, to kiss.
The kings and judges of the earth are exhorted to kiss the Son when He comes to reign, lest his wrath break loose and they perish (Ps. 2:12).
In the “Apostolic Constitutions”, a writing compiled in the 4th century AD, there is reference to the fact that then men and women sat separately on different sides of the room, so the kiss did not then occur between people of different sexes.