If we cannot trust other people unconditionally, what degree of loyalty do we owe to our friends? Aristotle offers two criteria for weighing our obligations. First of all, he believes that “it is our sacred duty to honor truth more highly [than friends].” Second, Aristotle states that our obligations to a friend should be weighed “in terms of the closeness of his relation to us and in terms of his excellence or usefulness.” He thus implies that we owe the highest loyalty to our families and to those who are useful to us. Cicero is more generous than Aristotle in this regard, adding that “old friendships must always have their proper place reserved for them, for nothing carries the weight of the old and familiar.” Thus our friends deserve the highest degree of loyalty when they are familiar as well as beneficial and closely related to us.
In contrast, what situations demand that we break off our relations? According to Aristotle, one factor in the dissolution of friendship is a change in virtue: “If one partner were to remain as he was, while the other became better and far outdistanced him in excellence, ought the latter to treat the former as a friend? Surely, that is impossible…. How could they still be friends, when they neither like nor feel joy and pain at the same things?” Cicero expresses a parallel sentiment: “The good cannot be friends with the wicked, nor the wicked with the good: there lies between them the widest imaginable gap in character and in interests.” Both writers believe that a divergence of interests (caused by a change in virtue) makes it impossible to maintain a friendship. In regard to those who have fallen from virtue, Aristotle qualifies his statement by saying that the friendship should not be broken off unless “a friend’s wickedness has become incurable… If there is a chance of reforming him, we must come to the aid of his character…” There seem to be certain situations that demand the end of a friendship. In the words of Cicero,
It happens many times in life that important considerations compel us to part from our friends. Anyone who tries to keep us from doing what we must and should in such cases, simply because he cannot bear the thought of losing us, is weak and self-indulgent, and for that very reason no true friend.
The pre-Christian writers focus on human affection in relation to personal needs rather than in relation to the Christian virtue of charity. Herbert Deane, developing the Christian theme of love of neighbor as presented by Saint Augustine, writes that
…when we are commanded to love our neighbor as ourselves, we are meant to apply this injunction to all men, and not simply to our friends or relatives. There is accordingly no one in the whole human family to whom kindly affection is not due by reason of the bond of a common humanity, although it may not be due on the ground of reciprocal love…. Love and kindly affection are due to all men, even to our enemies…
Embracing a Christian way of living does not mean that our enemies should become our friends, but it does require a generous attitude toward adversaries, thus outstripping pre-Christian ideas vis-a-vis human relations.