Duties are universally measured by relations. Is a certain man your father? In this are implied taking care of him, submitting to him in all things, patiently receiving his reproaches, his correction. But he is a bad father. Is your natural tie, then, to a _good_ father? No, but to a father. Is a brother unjust? Well, preserve your own just relation toward him. Consider not what _he_ does, but what _you_ are to do to keep your own will in a state conformable to nature, for another cannot hurt you unless you please. You will then be hurt when you consent to be hurt. In this manner, therefore, if you accustom yourself to contemplate the relations of neighbor, citizen, commander, you can deduce from each the corresponding duties. XXXI Be assured that the essence of piety toward the gods lies in this—to form right opinions concerning them, as existing and as governing the universe justly and well. And fix yourself in this resolution, to obey them, and yield to them, and willingly follow them amidst all events, as being ruled by the most perfect wisdom. For thus you will never find fault with the gods, nor accuse them of neglecting you. And it is not possible for this to be affected in any other way than by withdrawing yourself from things which are not within our own power, and by making good or evil to consist only in those which are. For if you suppose any other things to be either good or evil, it is inevitable that, when you are disappointed of what you wish or incur what you would avoid, you should reproach and blame their authors. For every creature is naturally formed to flee and abhor things that appear hurtful and that which causes them; and to pursue and admire those which appear beneficial and that which causes them. It is impracticable, then, that one who supposes himself to be hurt should rejoice in the person who, as he thinks, hurts him, just as it is impossible to rejoice in the hurt itself. Hence, also, a father is reviled by his son when he does not impart the things which seem to be good; and this made Polynices and Eteocles[4] mutually enemies—that empire seemed good to both. On this account the husbandman reviles the gods; [and so do] the sailor, the merchant, or those who have lost wife or child. For where our interest is, there, too, is piety directed. So that whoever is careful to regulate his desires and aversions as he ought is thus made careful of piety likewise. But it also becomes incumbent on everyone to offer libations and sacrifices and first fruits, according to the customs of his country, purely, and not heedlessly nor negligently; not avariciously, nor yet extravagantly. XXXII