Sayyida Umm Fadl bint Harith (may Allah be pleased with her) narrates: Some people, in her presence, differed regarding the fasting of the Prophet (peace be upon him) on the day of Arafah. Some people said that the Prophet (peace be upon him) was fasting, while others said that the Prophet (peace be upon him) was not fasting. So Sayyida Umm Fadl (may Allah be pleased with her) sent a bowl of milk to the Prophet (peace be upon him). At that time, he was standing on his camel, so the Prophet (peace be upon him) drank it.
Hadith Referenceصحیح ابن حبان / كتاب الصوم / 3606
Hadith Gradingفضيلة الشيخ الإمام محمد ناصر الدين الألبانيصحيح - «صحيح أبي داود» (2109): ق.فضيلة الشيخ العلّامة شُعيب الأرناؤوطإسناده صحيح على شرطهما