Self-knowledge is indispensable for growth in virtue, and genuine friends provides a person with a sort of mirror with which to see himself more clearly. Further, friendship involves a sort of healthy competition for virtue between the friends, by which each spurs the other on to greater virtue. There is no element of antagonism in this sort of a competition, but rather a sort of mutual encouragement. Friends also help each other to grow in virtue by correcting one another, encouraging one another in virtue, and providing good example to one another. In all situations of life, friendship is choiceworthy.
Friends appear to be the greatest of human goods.
Even for a man who is most blessed in terms of virtue, wealth, honors and so on cannot be truly blessed without friends, for such relationships are a necessity of human nature.