Musannaf Ibn Abi Shaybah

Hazrat Hassan bin Atiyyah narrates that once a man was riding a donkey when suddenly he fell off and said, "I have fallen from the donkey." The angel on the right said, "This is not a good deed that I should record it," and the angel on the left said, "What kind of sin is this that I should record it?" Then the angel on the left was instructed, "Record whatever statement the right (angel) leaves unrecorded."