What I know for sure is that if you can survive 11 days in cramped quarters with a friend and come out laughing, your friendship is the real deal. I know ours is.
Genuine human friendship is on the basis of human affection, irrespective of your position. Therefore, the more you show concern about the welfare and rights of others, the more you are a genuine friend. The more you remain open and sincere, then ultimately more benefits will come to you. If you forget or do not bother about others, then eventually you will lose your own benefit.
It is not merely true that a creed unites men. Nay, a difference of creed unites men - so long as it is a clear difference. A boundary unites. Many a magnanimous Moslem and chivalrous Crusader must have been nearer to each other, because they were both dogmatists, than any two agnostics. "I say God is One," and "I say God is One but also Three," that is the beginning of a good quarrelsome, manly friendship.
No man is an island, entire of itself; every man is a piece of the continent, a part of the main. If a clod be washed away by the sea, Europe is the less, as well as if a promontory were, as well as if a manor of thy friend's or of thine own were: any man's death diminishes me, because I am involved in mankind, and therefore never send to know for whom the bells tolls; it tolls for thee.
Sometimes in our relationship to another human being the proper balance of friendship is restored when we put a few grains of impropriety onto our own side of the scale.
The rule of friendship means there should be mutual sympathy between them, each supplying what the other lacks and trying to benefit the other, always using friendly and sincere words.
Go face the fire at sea, or the cholera in your friend's house, or the burglar in your own, or what danger lies in the way of duty, knowing you are guarded by the cherubim of Destiny. If you believe in Fate to your harm, believe it, at least, for your good.
Then, though I prize my friends, I cannot afford to talk with them and study their visions, lest I lose my own. It would indeed give me a certain household joy to quit this lofty seeking, this spiritual astronomy, or search of stars, and come down to warm sympathies with you; but then I know well I shall mourn always the vanishing of my mighty gods.