Sahih Bukhari Volume 001, Book 004, Hadith Number 170.
Narated By Anas bin Malik : Saw Allah's Apostle when the 'Asr prayer was due and the people searched for water to perform ablution but they could not find it. Later on (a pot full of) water for ablution was brought to Allah's Apostle . He put his hand in that pot and ordered the people to perform ablution from it. I saw the water springing out from underneath his fingers till all of them performed the ablution (it was one of the miracles of the Prophet).