14 Beware also of a blabbing tongue and of itching ears. Neither detract from others nor listen to detractors. “You sit,” says the psalmist, “and speakest against your brother; you slander your own mother's son. These things have you done and I kept silence; you thought wickedly that I was such an one as yourself, but I will reprove you and set them in order before your eyes.” Keep your tongue from cavilling and watch over your words. Know that in judging others you are passing sentence on yourself and that you are yourself guilty of the faults which you blame in them. It is no excuse to say: “if others tell me things I cannot be rude to them.” No one cares to speak to an unwilling listener. An arrow never lodges in a stone: often it recoils upon the shooter of it. Let the detractor learn from your unwillingness to listen not to be so ready to detract. Solomon says:— “meddle not with them that are given to detraction: for their calamity shall rise suddenly; and who knows the destruction of them both?” — of the detractor, that is, and of the person who lends an ear to his detraction.
Source: Letters (New Advent)