Musnad Ahmad 937:104

Waki’ narrated to us, al-A’mash narrated to us, from al-Ma’rur ibn Suwayd, from Abu Dharr, who said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "A man will be brought on the Day of Resurrection, and it will be said: 'Present his minor sins to him.' So they will be presented to him, and his major sins will be hidden from him. It will be said: 'You did such and such on such and such a day, and such and such on such and such a day.' He will acknowledge it and will not deny it, while he is fearful of the major ones. Then it will be said: 'Give him a good deed in place of every evil deed he committed.' He will say: 'Indeed, I have sins that I do not see here.'" He (the narrator) said: Abu Dharr said: I saw the Messenger of Allah (peace and blessings of Allah be upon him) laugh until his molar teeth appeared.