Diogenes Laertius Vitae philosophorum 7.1.23

[23] Again he would say that if we want to master the sciences there is nothing so fatal as conceit, and again there is nothing we stand so much in need of as time. To the question Who is a friend? his answer was, A second self ( alter ego). We are told that he was once chastising a slave for stealing, and when the latter pleaded that it was his fate to steal, Yes, and to be beaten too, said Zeno. Beauty he called the flower of chastity, while according to others it was chastity which he called the flower of beauty. ¹ Once when he saw the slave of one of his acquaintance marked with weals, I see, said he, the imprints of your anger. To one who had been drenched with unguent, Who is this, quoth he, who smells of woman? When Dionysius the Renegade asked, Why am I the only pupil you do not correct? the reply was, Because I mistrust you. To a stripling who was talking nonsense his words were, The reason why we have two ears and only one mouth is that we may listen the more and talk the less.