Marcus Tullius Cicero. Thoughts and sayings (№ 454273)

Let us consider what a powerful remedy philosophy gives us against diseases of the soul. These means undoubtedly exist, and nature was not so hostile to the human race that, having squandered so many substances useful for the body, it did nothing for the soul. On the contrary, she showed us all the more affection because the medicines for the body are outside of us, and the medicines for the soul are contained in herself. But the more, the more divine their action, the more attention should be used with them. Reason will show us these medicines, a mind which, well directed, will always discover the highest good, and which, if neglected, falls into a thousand errors.