He who has learned that prosperity and peace consist in not missing what we seek, or suffering what we shun, keeps down his desires, and shuns only what he can avoid.
Epictetus' Discourses, book i, chap, iv, sec. 1
Whoever shuns, or desires, what is not in his own power, cannot be either faithful or free.
Epictetus' Discourses, book i, chap, iv, sec. 19.