Musnad Abu Ya'la al-Mawsili 155:124

Muhammad ibn Ishaq al-Musayyibi narrated to us, he said: Anas ibn Iyad narrated to me, from Yunus, from al-Zuhri, that he said: Abu Salamah ibn Abd al-Rahman informed me, from Abu Hurayrah, that the Messenger of Allah (may Allah bless him and grant him peace) said: "Indeed, the Shaytan comes to one of you until he does not know how much he has prayed. So if he does that, then let him prostrate two prostrations while he is sitting."