Most people prefer receiving to giving affection, and equate receiving affection and having many friends with honor or prestige. The essence of friendship, however, is giving affection. The relationship of mothers and children is a good example of this. It is typical of mothers to give more affection than they receive, and they seem to find all the pleasure they require in seeing their children happy and prosperous, even if they do not receive what might be considered their due in respect and affection.
Of course friendship is reciprocal and requires two parties. If giving affection is the essence of friendship and the proper virtue of friends, then both parties must give affection to each other. It is this which ensures the strength and stability of friendships. The exchange of affection provides the basis for friendships between unequals, since equality can be established by a proportion between the amount of affection each party gives the other.
Unequal or opposite partners are most often found in friendships of utility, where each partner gives the other something he lacks and receives in return something he himself does not have. This kind of relationship is a union of opposites, perhaps due to some natural human urge to try to strike a balance or mean between opposing things or states.