And they all wept sore, and fell on Paul’s neck, and kissed him, Acts 20:37

Salute one another with an holy kiss. The churches of Christ salute you. Rom.16:16

All the brethren greet you. Greet ye one another with an holy kiss.1 Cor.16:20

Greet one another with an holy kiss. 2 Cor. 13:12

Greet all the brethren with an holy kiss. 1 Thess. 5:26

Greet ye one another with a kiss of charity. Peace be with you all that are in Christ Jesus. Amen. 1 Peter 5:14

Therefore the kiss, or rather the salutation, should be given with the greatest care, since, if there be mixed with it the least defilement of thought, it excludes us from eternal life.Athenagorus (A.D. 137) Ante-Nicene Fathers vol.2 pg.146

But love is not proved by a kiss, but by kindly feeling. But there are those, that do nothing but make the churches resound with a kiss, not having love itself within. For this very thing, the shameless use of a kiss, which ought to be mystic, occasions foul suspicions and evil reports. The apostle calls the kiss holy. When the kingdom is worthily tested, we dispense the affection of the soul by a chaste and closed mouth, by which chiefly gentle manners are expressed. Clement of Alexandria (A.D. 195) Ante-Nicene Fathers vol.2 pg.291

Accordingly, he says, they were both led away together (to be martyred), and on the way the other asked James to forgive him. And he, considering a little, said, “Peace be to you” and kissed him. And so both were beheaded together. Clement of Alexandria (A.D. 195) Ante-Nicene Fathers vol.2 pg.579

But even if there be some reason far this practice, still, lest you offend against this precept, you may perhaps defer your “peace” at home, where it is not possible for your fast to be entirely kept secret. But wherever else you can conceal your observance, you ought to remember the precept: thus you may satisfy the requirements of Discipline abroad and of custom at home. So, too, on the day of the Passover, when the religious observance of a fast is general, and as it were public, we justly forego the kiss, caring nothing to conceal anything which we do in common with all.Tertullian (A.D. 198) Ante-Nicene Fathers vol.3 pg. 687