Sahih Bukhari Volume 1, Book 12, Hadith Number 820

Narated By Ibn ‘Abbas : Once I came riding a she-ass and I, then, had just attained the age of puberty. Allah’s Apostle was leading the people in prayer at Mina facing no wall. I passed in front of the row and let loose the she-ass for grazing and joined the row and no one objected to my deed.