Marcus Tullius Cicero,
The Academic Questions, Treatise De Finibus…
(1891)
“ Why, on this principle,—because we protect those things which are external with those duties which arise from their respective kinds of virtue. For the cultivation of the regard of a friend or a parent, which is the discharge of a duty, is advantageous in the actual fact of its being such, inasmuch as to discharge a duty is a good action; and good actions spring from virtues; and wise men attend to them, using nature as a kind of guide. ”
