Letters 66.37

The two kinds of goods which are of a higher order are different; the primary are according to nature,—such as deriving joy from the dutiful behaviour of one’s children and from the well-being of one’s country. The secondary are contrary to nature,—such as fortitude in resisting torture or in enduring thirst when illness makes the vitals feverish.

Seneca, Letters to Lucilius 66.37, translated by Richard Mott Gummere