St. Augustine, Confessions
4.8.13 (tr. Henry Chadwick):
There were other things which occupied my mind in the company of my friends: to make conversation, to share a joke, to perform mutual acts of kindness, to read together well-written books, to share in trifling and serious matters, to disagree though without animosity—just as a person debates with himself—and in the very rarity of disagreement to find the salt of normal harmony, to teach each other something or to learn from one another, to long with impatience for those absent, to welcome them with gladness on their arrival. These and other signs come from the heart of those who love and are loved and are expressed through the mouth, through the tongue, through the eyes, and a thousand gestures of delight, acting as fuel to set our minds on fire and out of many to forge unity.
alia erant quae in eis amplius capiebant animum, conloqui et conridere et vicissim benivole obsequi, simul legere libros dulciloquos, simul nugari et simul honestari, dissentire interdum sine odio tamquam ipse homo secum atque ipsa rarissima dissensione condire consensiones plurimas, docere aliquid invicem aut discere ab invicem, desiderare absentes cum molestia, suscipere venientes cum laetitia: his atque huius modi signis a corde amantium et redamantium procedentibus per os, per linguam, per oculos et mille motus gratissimos, quasi fomitibus conflare animos et ex pluribus unum facere.