Abu Dawud Book 1, Hadith Number 172.
Chapter : Offering various prayers with the same ablution.
Narated By N/A : Buraidah on the authority of his father reported: The Messenger of Allah (may peace be upon him) performed five prayers with the same ablution on the occasion of the capture of Mecca, and he wiped over his socks. ‘Umar said to him (the Prophet): I saw you doing a thing today that you never did. He said: I did it deliberately.