Musnad Abu Ya'la al-Mawsili 109:56

Al-Jarrah ibn Makhlad narrated to us, Yahya ibn Kathir ibn Dirham al-Anbari narrated to us, Abd al-Aziz ibn Rabi' al-Bahili narrated to us, from Ata ibn Rabah, from Jabir, who said: We were with the Messenger of Allah, may Allah bless him and grant him peace, on a journey, and he came upon two graves whose occupants were being punished. He said: "Indeed, they are being punished for something not major: backbiting and urine." Then he called for a palm branch and broke it, and placed a piece on each of them. He said: "I hope that it will be lightened for them as long as they do not dry out."