It is recommended for the person performing Hajj in 'Arafat not to fast on the day of 'Arafah. Sahih Muslim 1123 c
Arabic hadith text
حَدَّثَنِي زُهَيْرُ بْنُ حَرْبٍ، حَدَّثَنَا عَبْدُ الرَّحْمَنِ بْنُ مَهْدِيٍّ، عَنْ سُفْيَانَ، عَنْ سَالِمٍ أَبِي، النَّضْرِ بِهَذَا الإِسْنَادِ نَحْوَ حَدِيثِ ابْنِ عُيَيْنَةَ وَقَالَ عَنْ عُمَيْرٍ، مَوْلَى أُمِّ الْفَضْلِ
Translation
This hadith has been narrated by Abu Nadr on the authority of Umair, the freed slave of Umm al-Fadl, through the same chain of transmitters.