كتاب الصيام
13  
The Book of Fasting
(18)
Chapter: It is recommended for the person performing Hajj in 'Arafat not to fast on the day of 'Arafah.
(18)
باب اسْتِحْبَابِ الْفِطْرِ لِلْحَاجِّ بِعَرَفَاتٍ يَوْمَ عَرَفَةَ ‏‏
Sahih Muslim 1123 b

This hadith has been narrated on the authority of Abu Nadr with the same chain of transmitters, but he did not mention that he was mounting (riding on) his camel.

حَدَّثَنَا إِسْحَاقُ بْنُ إِبْرَاهِيمَ، وَابْنُ أَبِي عُمَرَ، عَنْ سُفْيَانَ، عَنْ أَبِي النَّضْرِ، بِهَذَا الإِسْنَادِ ‏.‏ وَلَمْ يَذْكُرْ وَهُوَ وَاقِفٌ عَلَى بَعِيرِهِ ‏.‏ وَقَالَ عَنْ عُمَيْرٍ مَوْلَى أُمِّ الْفَضْلِ ‏.‏
Reference : Sahih Muslim 1123b
In-book reference : Book 13, Hadith 139
USC-MSA web (English) reference : Book 6, Hadith 2495
  (deprecated numbering scheme)