EPICTETUS. DISCOURSES. Book ii. §22. ¶2.
WHENEVER, therefore, anyone makes his interest to consist in the same thing with sanctity, virtue, his country, parents, and friends, all these are secured; but wherever they are made to interfere, friends, and country, and family, and justice itself, all give way, borne down by the weight of self-interest. For wherever I and mine are placed, thither must every animal gravitate. If in body, that will sway us; if in choice, that; if in externals, these. If, therefore, I be placed in a right choice, then only I shall be a friend, a son, or a father, such as I ought. For in that case it will be for my interest to preserve the faithful, the modest, the patient, the abstinent, the beneficent character; to keep the relations of life inviolate. But, if I place myself in one thing, and virtue in another, the doctrine of Epicurus will stand its ground, That virtue is nothing, or mere opinion.