The word "fraternity" or "friendship" names one of the three major forms of love. All the forms of love involve benevolent impulses toward another, none is an expression of purely selfish desire.
Friendship or fraternity is natural, not supernatural, love, as is charity or the love of God. It is also a form of love that involves no erotic or sexual component. It is the love that a human being wills to another. The person loved is also a person in whose company one wishes to live and upon whom to confer benefits; in any way possible.
If all men were friends, Aristotle tells us, there would be no need for justice. The precepts of friendly love are all positive, and the precepts of justice are mainly negative. Prohibiting injury to others.