Musnad Ahmad 937:114

Waki’ and ‘Abd al-Rahman narrated to us, from Sufyan, from Habib, from Maymun, from Abu Dharr. ‘Abd al-Rahman said: I said, "O Messenger of Allah, advise me." He said: "Fear Allah wherever you are, and follow up a bad deed with a good deed, it will erase it, and treat people with good character." Waki’ had narrated it to us from Maymun ibn Abi Shabib, from Mu’adh, then he retracted it.