Letter 81 (§13)

“These men, accordingly, should cease to discredit us, just as if we were uttering an impossible boast; they should understand that the essence of honour resides in the wise man, while among the crowd we find only the ghost and the semblance of honour. None but the wise man knows how to return a favour. Even a fool can return it in proportion to his knowledge and his power; his fault would be a lack of knowledge rather than a lack of will or desire. To will does not come by teaching.”