Abu Dawud
Purification (Kitab Al-Taharah)
Book Number: 001 / Hadith Number: 107
Narated By Humran : I saw 'Uthman b. 'Affan performing ablution. He then narrated the same tradition. In this version there is no mention of rinsing of mouth and snuffing of water. This tradition adds: "He wiped his head three times. He then washed his feet three times. He then said: I saw the Apostle of Allah (pbuh) performing ablution in this manner. He (the Prophet) said: He who performs ablution like this, it is sufficient for him. The narrator did not mention prayer (in this tradition).