Sahih Muslim Book - 13, Hadith - 2635

وَحَدَّثَنِى هَارُونُ بْنُ سَعِيدٍ الأَيْلِىُّ حَدَّثَنَا ابْنُ وَهْبٍ أَخْبَرَنِى عَمْرٌو أَنَّ أَبَا النَّضْرِ حَدَّثَهُ أَنَّ عُمَيْرًا مَوْلَى ابْنِ عَبَّاسٍ - رضى الله عنهما - حَدَّثَهُ أَنَّهُ سَمِعَ أُمَّ الْفَضْلِ - رضى الله عنها - تَقُولُ شَكَّ نَاسٌ مِنْ أَصْحَابِ رَسُولِ اللَّهِ -صلى الله عليه وسلم- فِى صِيَامِ يَوْمِ عَرَفَةَ وَنَحْنُ بِهَا مَعَ رَسُولِ اللَّهِ -صلى الله عليه وسلم- فَأَرْسَلْتُ إِلَيْهِ بِقَعْبٍ فِيهِ لَبَنٌ وَهُوَ بِعَرَفَةَ فَشَرِبَهُ.

Umair, the freed slave of Ibn Abbas [may Allah be pleased with them], narrated that he heard Umm Al-Fadl [may Allah be pleased with her] say: “Some of the companions of Messenger of Allah were unsure about the fasting on the Day of Arafah when we were there with the Messenger of Allah (SAW). I sent a wooden vessel of milk when he was at Arafat, and he drank it.”