Military Expeditions led by the Prophet (pbuh) (Al-Maghaazi)
Bukhari :: Book 5 :: Volume 59 :: Hadith 696
Narrated 'Abdullah bin 'Abbas:
That he came riding a donkey when Allah 's Apostle was standing at Mina during Hajjat-ul-Wada', leading the people in prayer. The donkey passed in front of a part of the row (of the people offering the prayer). Then he dismounted from it and took his position in the row with the people.