Musannaf Ibn Abi Shayba 17:1196

Ghundar narrated to us, from Shu'bah, from al-Hakam, who said: I heard 'Urwah ibn al-Nazzal narrating from Mu'adh ibn Jabal that the Prophet, may Allah bless him and grant him peace, said to him: "Shall I not guide you to the master of all that?" He said: I said, "O Messenger of Allah, [tell me] your statement: 'Shall I not guide you to the master of all that?'" He said: The Messenger of Allah, may Allah bless him and grant him peace, pointed to his tongue. He said: I said, "O Messenger of Allah, and are we held accountable for what we speak?" He said: "May your mother be bereaved of you, O Mu'adh! And does anything cast people upon their faces—or he said: upon their noses—except the harvests of their tongues?" Shu'bah said: And al-Hakam said: And Maymun ibn Abi Shabib narrated it to me, and I heard it from him forty years ago.