Sahih Bukhari Volume 001, Book 004, Hadith Number 187.
Narated By Abu Juhaifa : Allah's Apostle came to us at noon and water for ablution was brought to him. After he had performed ablution, the remaining water was taken by the people and they started smearing their bodies with it (as a blessed thing). The Prophet offered two Rakat of the Zuhr prayer and then two Rakat of the 'Asr prayer while an 'Anza (spear-headed stick) was there (as a Sutra) in front of him. Abu Musa said: The Prophet asked for a tumbler containing water and washed both his hands and face in it and then threw a mouthful of water in the tumbler and said to both of us (Abu Musa and Bilal), "Drink from the tumbler and pour some of its water on your faces and chests."