…We could talk and laugh together and exchange small acts of kindness. We could join in the pleasure that books can give. We could be grave or [happy] together. If we sometimes disagreed, it was without spite, as a man might differ with himself, and the rare occasions of dispute were the very spice to season our usual accord. Each of us had something to learn from the others and something to teach in return. If any were away, we missed them with regret and gladly welcomed them when they came home. Such things as these are heartfelt tokens of affection between friends. They are signs to be read on the face and in the eyes, spoken by the tongue and displayed in countless acts of kindness. They can kindle a blaze to melt our hearts and weld them into one.
This what we cherish in friendship, and we cherish it so dearly that in conscience we feel guilty if we do not return love for love, asking no more of our friends than these expressions of goodwill. This is why we mourn their death, which shrouds us in sorrow and turns joy into bitterness, so that the heart is drenched in tears and life becomes a living death because a friend is lost. Blessed are those who love you, O God, and love their friends in you and their enemies for your sake. They alone will never lose those who are dear to them, for they love them in one who is never lost, in God, our God who made heaven and earth and fills them with his presence, because by filling them he made them. No one can lose you, my God, unless he forsakes you. And if he forsakes you, where is he to go? If he abandons your love, his only refuge is your wrath. Wherever he turns, he will find your law to punish them, for your law is the truth and the truth is yourself.
Augustine, The Confessions [BOOK IV]