Book VII · 37
It is a base thing for the countenance to be obedient and to regulate and compose itself as the mind commands, and for the mind not to be regulated and composed by itself.
It is a shame that while the countenance is subject to the mind, taking its cast and livery from it, the mind cannot take its cast and its livery from itself.
Marcus Aurelius, Meditations VII.37. Translated by George Long (1862). The Stoic Library.