Stobaeus on Stoic Ethics 6

They say, then, that these virtues just listed are perfect in our lives and consist of theorems; but others supervene on them, which are no longer crafts but rather certain capabilities that come as a result of practice, for example, health of the soul and its soundness and strength and beauty. 

For just as the health of the body is a good blend of the hot and cold and wet and dry elements in the body, so too the health of the soul is a good blend of the beliefs in the soul. 

And similarly, just as strength of the body is a sufficient tension in the sinews, so too the strength of the soul is a sufficient tension in judging and acting and in not doing so. 

And just as beauty of the body is a symmetry of its limbs constituted with respect to each other and to the whole, so too the beauty of the soul is a symmetry of reason and its parts with respect to the whole of it and to each other. 

IMAGE:Leonardo da Vinci, Vitruvian Man (c. 1492)