(69) CHAPTER. Can the Imam depend on the people's saying if he is in doubt (about a certain matter)?
Narrated Abu Huraira: The Prophet prayed two rak`at of Zuhr prayer (instead of four) and he was told that he had prayed two rak`at only. Then he prayed two more rak`at and finished them with the Taslim followed by two prostrations.
Authentic