This perfected or completed friendship, for its aims do not go outside the friendship itself. Such friendships are virtuous because they conduce to the good. But perfected or completed friendships is not characteristic of most friendships. Virtuous or perfected friendship is possible only between those who are relevantly equal, though the measure of equality is not quantitative but proportional. The only degree of inequality that would entirely negate the possibility of friendship would be that which divides humanity from the gods.
Virtuous friendship is the ground and model for the good polis.
These virtues are partly innate but largely learned from masters. Moral excellence is also learned. Moral virtue is a mean between excesses, a balance point. Rage is not virtuous because it is excessive and uncontrolled. Courage is the virtue at the balance point between heedlessness and cowardice, which are both excessive forms of the same thing.