Clement of Alexandria: The Instructor

And if we are called to the kingdom of God, let us walk worthy of the kingdom, loving God and our neighbour. 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,^{Edition note 1} 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.^{Edition note 2}

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.

But there is another unholy kiss, full of poison, counterfeiting sanctity. Do you not know that spiders, merely by touching the mouth, afflict men with pain? And often kisses inject the poison of licentiousness. It is then very manifest to us, that a kiss is not love. For the love meant is the love of God. “And this is the love of God,” says John, “that we keep His commandments;”^{Edition note 3} not that we stroke each other on the mouth. “And His commandments are not grievous.” But salutations of beloved ones in the ways, full as they are of foolish boldness, are characteristic of those who wish to be conspicuous to those without, and have not the least particle of grace.

For if it is proper mystically “in the closet” to pray to God, it will follow that we are also to greet mystically our neighbour, whom we are commanded to love second similarly to God, within doors, “redeeming the time.” “For we are the salt of the earth.”^{Edition note 4} “Whosoever shall bless his friend early in the morning with a loud voice, shall be regarded not to differ from cursing.”^{Edition note 5}