Sayyidah Maymunah (may Allah be pleased with her) narrates that the people were in doubt about the fasting of the Messenger of Allah (peace and blessings be upon him) on the Day of Arafah, so Sayyidah Maymunah (may Allah be pleased with her) sent milk to the Messenger of Allah (peace and blessings be upon him) while he (peace and blessings be upon him) was standing at the place of standing (mawqif), and he (peace and blessings be upon him) drank from it while the people were watching.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصيام / 8386