Enchiridion 9

Disease is an impediment to the body, but not to the moral purpose, unless that consents. Lameness is an impediment to the leg, but not to the moral purpose. And say this to yourself at each thing that befalls you; for you will find the thing to be an impediment to something else, but not to yourself.

Epictetus, Enchiridion 9, translated by W. A. Oldfather

Disease is an impediment to the body, but not to the will, unless the will itself chooses. Lameness is an impediment to the leg, but not to the will. And add this reflection on the occasion of every thing that happens; for you will find it an impediment to something else, but not to yourself.

Epictetus, Enchiridion 9, translated by George Long

Sickness is a hindrance to the body, but not to the will, unless the will consent. Lameness is a hindrance to the leg, but not to the will. Say this to yourself at each event that happens, for you shall find that though it hinders something else it will not hinder you.

Epictetus, Enchiridion 9, translated by P. E. Matheson