(18) باب اسْتِحْبَابِ الْفِطْرِ لِلْحَاجِّ بِعَرَفَاتٍ يَوْمَ عَرَفَةَ
Kuraib, the freed slave of Ibn 'Abbas (Allah be pleased with him), reported from Maimuna, the wife of the Messenger of Allah (ﷺ), that people had doubt about the fasting of Allah's Messenger (ﷺ) on the day of 'Arafa. Maimuna sent him a cup of milk and he was halting at a place and he drank it and the people were seeing him.
Reference: Sahih Muslim 1124
In-book reference: Book 13, Hadith 142
USC-MSA web (English) reference(deprecated numbering scheme): Book 6, Hadith 2498