Abu Dawud Book 2, Hadith Number 1031.
Chapter : Not known.
Narated By Al-Mughirah ibn Shu’bah : The Prophet (PBUH) said: When an imam stands up at the end of two rak’ahs , if he remembers before standing straight up, he should sit down, but if he stands straight up, he must not sit down, but perform the two prostrations of forgetfulness.