Enchiridion 38

Just as you are careful, in walking about, not to step on a nail or to sprain your ankle, so be careful also not to hurt your governing principle. And if we observe this rule in every action, we shall be more secure in setting about it.

Epictetus, Enchiridion 38, translated by W. A. Oldfather

In walking about as you take care not to step on a nail or to sprain your foot, so take care not to damage your own ruling faculty: and if we observe this rule in every act, we shall undertake the act with more security.

Epictetus, Enchiridion 38, translated by George Long

As in walking you take care not to tread on a nail or to twist your foot, so take care that you do not harm your Governing Principle. And if we guard this in everything we do, we shall set to work more securely.

Epictetus, Enchiridion 38, translated by P. E. Matheson