Musnad Ahmad 443:0

Narrated to us by Hisham ibn Muhammad, from his father, from Habis ibn Sa’d al-Ta’i, who said: I came to the Messenger of Allah (peace be upon him) while he was sitting, and 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, for it will erase it, and treat people with good character."