Yahya related to me from Malik from Hisham ibn Urwa from hisfather that A'isha, the wife of the Prophet, may Allah bless him andgrant him peace, said, "An infant boy was brought to the Messenger ofAllah, may Allah bless him and grant him peace, and it urinated onhim. The Messenger of Allah, may Allah bless him and grant him peace,called for some water and rubbed over the urine with it."
USC-MSA web (English) reference: Book 2, Hadith 111
Arabic reference: Book 2, Hadith 140