It was narrated from 'Amr bin Shu'aib from his father, from his grandfather, that:
A Bedouin came to the Prophet and asked him about ablution. He showed him how to perform it washing each part of the body three times. Then he said: 'This is the ablution, and whoever does more than this, has done evil, transgressed the limits and wronged himself.'"
English reference: Vol. 1, Book 1, Hadith 422
Arabic reference: Book 1, Hadith 457