Abu Dawud Book 1, Hadith Number 120.

Chapter : A man who puts his hands in the utensil before washing it.

Narated By N/A : Habban b. Wasi’ reported on the authority of his father who heard ‘Abd Allah b. Zaid al-‘Asim al-Mazini say that he saw the Messenger of Allah (may peace be upon him) performing ablution. He then described his ablution saying: He wiped his head with water which was not what was left over after washing his hands (i.e. he wiped his head with clean water); then he washed his feet until he cleansed them.