The people doubted whether the Prophet ﷺ was observing the fast on the Day of ʿArafat, so I sent something for him to drink and he drank it.  

عَنْ أُمِّ الْفَضْلِ شَكَّ النَّاسُ يَوْمَ عَرَفَةَ فِي صَوْمِ النَّبِيِّ ﷺ فَبَعَثْتُ إِلَى النَّبِيِّ ﷺ بِشَرَابٍ فَشَرِبَهُ