Musnad Abu Ya'la al-Mawsili 106:22

Ibrahim ibn Dinar narrated to us, Mus'ab ibn Salam narrated to us, from Hamzah ibn Habib al-Zayyat, from Abu Ishaq al-Sabi'i, from al-Bara' who said: The Messenger of Allah (may Allah bless him and grant him peace) delivered a sermon to us until he made the young women in their houses—or he said: in their private quarters—hear. He said: "O assembly of those who have believed with their tongues, do not backbite the Muslims and do not pursue their faults. For whoever pursues the fault of his brother, Allah will pursue his fault; and whoever Allah pursues his fault, He will expose him in the interior of his house."