Friends enhance our ability to think and act.

If a man of good natural disposition acquires Intelligence [as a whole], then he excels in conduct, and the disposition which previously only resembled Virtue, will now be Virtue in the true sense. Hence just as with the faculty of forming opinions [the calculative faculty] there are two qualities, Cleverness and Prudence, so also in the moral part of the soul there are two qualities, natural virtue and true Virtue; and true Virtue cannot exist without Prudence.

Nature does nothing in vain. Therefore, it is imperative for persons to act in accordance with their nature and develop their latent talents, in order to be content and complete.

Fine friendship requires duration rather than fitful intensity.

We become just by the practice of just actions.

Therefore the good man ought to be a lover of self, since he will then both benefit himself by acting nobly and aid his fellows; but the bad man ought not to be a lover of self, since he will follow his base passions, and so injure both himself and his neighbors. With the bad man therefore, what he does is not in accord with what he ought to do, but the good man does what he ought, since intelligence always chooses for itself that which is best, and the good man obeys his intelligence.

When...we, as individuals, obey laws that direct us to behave for the welfare of the community as a whole, we are indirectly helping to promote the pursuit of happiness by our fellow human beings.