1 Thessalonians 5:26 - Ellicott's Commentary On The Whole Bible

Greet all the brethren. — It is concluded from the manner in which some are told to greet all, instead of all being told to greet one another (as in the parallel passages), that the “brethren” to whom the letter was sent specially were the priesthood of Thessalonica (comp. the next verse). If so, the “holy kiss” had hardly become the fixed Church ceremony which it afterwards was, for the practice (according to the Apostolicqal Constitutions) was for the Church members to pass the kiss from one to another, men kissing men, and women kissing women, not for all the people to be kissed in turn by the priest. This kiss, however, is no doubt intended by St. Paul to be given at a solemn assembly of the Church, i.e., at the Holy Communion, which was the only fixed meeting of the Primitive Church. In the time of St. Cyril of Jerusalem, the kiss was given just before the Sursum Corda. It was not till the thirteenth century that the kissing of the Pax was substituted in the Western Church for the kissing of the brethren. This kiss was to differ from the ordinary Greek salutation, by being distinctly a holy kiss, i.e., a ceremonial, religious kiss.