Sahih Bukhari
Ablutions (Wudu)
Volume: 001 / Book Number: 004 / Hadith Number: 196
Narrated 'Abdullah bin Zaid:
Once Allah's Apostle came to us and we brought out water for him in a brass pot. He performed ablution thus: He washed his face thrice, and his forearms to the elbows twice, then passed his wet hands lightly over the head from front to rear and brought them to front again and washed his feet (up to the ankles).