Sahih Muslim Book 6, Hadith 29
I prayed with the Messenger of Allah (ﷺ) two rak'ahs and most of them offered two rak'ahs only in Mina, while the people felt secure.
A hadith like this has been reported by A'mash with the same chain of transmitters.
I prayed behind the Messenger of Allah (ﷺ) at Mina, and there was the greatest number of people, and they prayed two rak'ahs on the occasion of the Farewell Pilgrimage. (Muslim said: Haritha b. Wahb al-Khuza'i is the brother of 'Ubaidullah b. 'Umar son of Khattab from the side of his mother.)