Sahih Muslim | Book 3 | Hadith Number 637

Narrated by Safina
Safina reported that Abd Bakr, the Companion of the Messenger of Allah (way peace be upon him), observed: The Messenger of Allah (may peace be upon him) took a bath with one Sa' of water and performed ablution with one Mudd (of water); and in the hadith narrated by Ibn Hujr the words are: One Mudd sufficed for his (Holy Prophet's) ablution. And Ibn Hujr said that (his Shaikh) Isma'il was much advanced in age, and it was because of this that he could not fully rely on him for this tradition.