Meditations 11.37

Epictetus also said, a man must discover an art [or rules] with respect to giving his assent; and in respect to his movements he must be careful that they be made with regard to circumstances, that they be consistent with social interests, that they have regard to the value of the object; and as to sensual desire, he should altogether keep away from it; and as to avoidance [aversion], he should not show it with respect to any of the things which are not in our power.

Marcus Aurelius, Meditations 11.37, translated by George Long

We must, says he, hit upon the true science of assent and in the sphere of our impulses pay good heed that they be subject to proper reservations, that they have in view our neighbour's welfare; that they are proportionate to worth. And we must abstain wholly from inordinate desire and shew avoidance in none of the things that are not in our control.

Marcus Aurelius, Meditations 11.37, translated by C. R. Haines