Yahya related to me from Malik from Abu'n Nadr, the mawla of Umaribn Ubaydullah, from Umayr, the mawla of Abdullah ibn Abbas, from Ummal-Fadl bint al-Harith, that she was present when some people werearguing on the day of Arafa about whether the Messenger of Allah, mayAllah bless him and grant him peace, was fasting or not. Some of themsaid he was fasting, and some of them said he was not. So she sent abowl of milk to him while his camel was standing still and he drank.
USC-MSA web (English) reference: Book 20, Hadith 133
Arabic reference: Book 20, Hadith 836