Sahih Muslim 504 c
This hadith has been narrated by Ibn 'Uyaina on the authority of al-Zuhri with the same chain of transmitters and he reported:
The Apostle of Allah (ﷺ) was leading prayer at 'Arafa.
حَدَّثَنَا يَحْيَى بْنُ يَحْيَى، وَعَمْرٌو النَّاقِدُ، وَإِسْحَاقُ بْنُ إِبْرَاهِيمَ، عَنِ ابْنِ عُيَيْنَةَ، عَنِ الزُّهْرِيِّ، بِهَذَا الإِسْنَادِ قَالَ وَالنَّبِيُّ صلى الله عليه وسلم يُصَلِّي بِعَرَفَةَ ‏.‏