Sahih Muslim Book 4, Hadith Number 1486.

Chapter : Compensation of the missed prayer and excellence of observing it promptly.

Wahb al-Khuza’i reported: I prayed behind the Messenger of Allah (way peace be upon him) at Mina, and there was the greatest number of people, and they prayed two rak’ahs on the occasion of the Farwell Pilgrimage. (Muslim said: Haritha b. Wahb al-Khuza’i is the brother of ‘Ubaidullah b. ‘Umar son of Khattab from the side of mother.)