Sen

“My advice is really this: what we hear the philosophers saying and what we find in their writings should be applied in our pursuit of the happy life. We should hunt out the helpful pieces of teaching, and the spirited and noble-minded sayings which are capable of immediate practical application—not far-fetched or archaic expressions or extravagant metaphors and figures of speech—and learn them so well that words become works. No one to my mind lets humanity down quite so much as those who study philosophy as if it were a sort of commercial skill and then proceed to live in a quite different manner from the way they tell other people to live.”
― Seneca, Letters from a Stoic