Sahih Bukhari Volume 001, Book 008, Hadith Number 373.

Narated By Abu Juhaifa : I saw Allah's Apostle in a red leather tent and I saw Bilal taking the remaining water with which the Prophet had performed ablution. I saw the people taking the utilized water impatiently and whoever got some of it rubbed it on his body and those who could not get any took the moisture from the others' hands. Then I saw Bilal carrying an 'Anza (a spear-headed stick) which he planted in the ground. The Prophet came out tucking up his red cloak, and led the people in prayer and offered two Rakat (facing the Ka'ba) taking 'Anza as a Sutra for his prayer. I saw the people and animals passing in front of him beyond the 'Anza.

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