Now, wheresoever you are, know, that I am with you, and you are so to live as if I both heard and saw you. Your letters are really blessings to me, and the sense of your improvements relieves me, even under the consideration of my own decay. Remember, that as I am old, so are you mortal. Be true to yourself, and examine yourself whether you be of the same mind to-day that you were yesterday; for that is a sign of perfect wisdom. And yet give me leave to tell you, that though change of mind be a token of imperfection, it is the business of my age to unwill one day that which I willed another. And let me recommend it to your practice too, in many cases; for the abatement of our appetites and of our errors is the best entertainment of mankind. It is for young men to gather knowledge, and for old men to use it: and assure yourself that no man gives a fairer account of his time than he that makes it his daily study to make himself better. If you be in health, and think it worth your while to become the master of yourself, it is my desire and my advice, that you apply yourself to wisdom with your whole heart, and judge of your improvement, not by what you speak, or by what you write, but by the firmness of your mind, and the government of your passions.
— Lucius Annaeus Seneca in Seneca’s Morals: By way of Abstract; To which is added, A Discourse, under the Title of An After-Thought, edited by Sir Roger L’Estrange, (London: by W. Bowyer for Jacob Tonson, 1702), Edition 8, p. 405. Originally published (London: by Tho. Newcomb for Henry Brome, 1679).