Volume 1, Book 11, Number 682:
Narrated Abu Huraira:
Once Allah’s Apostle prayed two Rakat (instead of four) and finished his prayer. Dhu-l-yadain
asked him whether the prayer had been reduced or whether he had forgotten. Allah’s Apostle asked
the people whether Dhu-l-yadain was telling the truth. The people replied in the affirmative. Then
Allah’s Apostle stood up, offered the remaining two Rakat and then finished his prayer with Taslim
and then said, “Allahu Akbar.” He followed it with two prostrations like ordinary prostrations or a bit
longer.