Friendship is a permanent disposition expressed or realized in friendly activities. Affection can be felt even for inanimate objects, but the reciprocal affection which is the basis of friendship involves deliberate choice, and such choice involves the action of a disposition. Affection is an emotion, but friendship is a characteristic or lasting attitude. In wishing the good of their friends for the sake of those friends, men are influenced not by emotion but by this disposition.
To love one's friends is to love one's own good, for the good man by the very act of befriending another becomes that other's good. Each friend loves his own good and makes the balance equal by wishing the good of the other. In this sense friendship is an equality. This is particularly evident in true friendship between good men.