Epistle XCIV — On the Value of Advice
Indeed, the persons who take the greatest pains to proffer such advice are themselves unable to put it into practice. …[I]t is the hottest-tempered school-master who contends that one should never lose one’s temper. Go to any elementary school, and you will learn that just such pronouncements, emanating from high-browed philosophers, are to be found in the lesson-book for boys!
Seneca Epistles 93-124, Translation by Richard Gummere. Loeb Classical Library.