Today is the feast of St. John Chrysostom, Doctor of the Church. From his Homilies on Colossians (Homily 1):
There are many causes which produce friendship; and we will pass over those which are infamous, (for none will take an objection against us in their favor, seeing they are evil.) But let us, if you will, review those which are natural, and those which arise out of the relations of life. Now of the social sort are these, for instance; one receives a kindness, or inherits a friend from forefathers, or has been a companion at table or in travel: or is neighbor to another (and these are virtuous); or is of the same trade, which last however is not sincere; for it is attended by a certain emulation and envy. But the natural are such as that of father to son, son to father, brother to brother, grandfather to descendant, mother to children, and if you like let us add also that of wife to husband; for all matrimonial attachments are also of this life, and earthly. Now these latter appear stronger than the former: appear, I said, because often they are surpassed by them. For friends have at times shown a more genuinely kind disposition than brothers, or than sons toward fathers; and when he whom a man has begotten would not succor him, one who knew him not has stood by him, and succored him. But the spiritual love is higher than all, as it were some queen ruling her subjects; and in her form is bright: for not as the other, has she anything of earth for her parent; neither habitual intercourse, nor benefits, nor nature, nor time; but she descends from above, out of heaven. And why do you wonder that she needs no benefits in order that she should subsist, seeing that neither by injuries is she overthrown?
Now that this love is greater than the other, hear Paul saying; For I could wish that I myself were anathema from Christ for my brethren.