text: You keep asking me to explain without postponement a topic which I once remarked should be put off until the proper time, and to inform you by letter whether this department of philosophy which the Greeks call paraenetic, and we Romans call the "preceptorial," is enough to give us perfect wisdom. Now I know that you will take it in good part if I refuse to do so. But I accept your request all the more willingly, and refuse to let the common saying lose its point: