From Sahih Bukhari (Hadith 5618):
Narrated Um Al-Fadl:(daughter of Al-Harith) that she sent a bowl of milk to the Prophet (ﷺ) while he was standing (at `Arafat) in the afternoon of the Day of `Arafat. He took it in his hands and drank it. Narrated Abu Nadr: The Prophet was on the back of his camel
Reference: Bukhari 5618