Sahih al-Bukhari 4606Book 65, Hadith 128
حَدَّثَنَا مُحَمَّدُ بْنُ بَشَّارٍ، حَدَّثَنَا عَبْدُ الرَّحْمَنِ، حَدَّثَنَا سُفْيَانُ، عَنْ قَيْسٍ، عَنْ طَارِقِ بْنِ شِهَابٍ، قَالَتِ الْيَهُودُ لِعُمَرَ إِنَّكُمْ تَقْرَءُونَ آيَةً لَوْ نَزَلَتْ فِينَا لاَتَّخَذْنَاهَا عِيدًا. فَقَالَ عُمَرُ إِنِّي لأَعْلَمُ حَيْثُ أُنْزِلَتْ، وَأَيْنَ أُنْزِلَتْ، وَأَيْنَ رَسُولُ اللَّهِ صلى الله عليه وسلم حِينَ أُنْزِلَتْ يَوْمَ عَرَفَةَ، وَإِنَّا وَاللَّهِ بِعَرَفَةَ ـ قَالَ سُفْيَانُ وَأَشُكُّ كَانَ يَوْمَ الْجُمُعَةِ أَمْ لاَ – {الْيَوْمَ أَكْمَلْتُ لَكُمْ دِينَكُمْ}
The Jews said to `Umar, "You (i.e. Muslims) recite a Verse, and had it been revealed to us, we would have taken the day of its revelation as a day of celebration." `Umar said, "I know very well when and where it was revealed, and where Allah's Messenger (ﷺ) was when it was revealed. (It was revealed on) the day of `Arafat (Hajj Day), and by Allah, I was at `Arafat" Sufyan, a sub-narrator said: I am in doubt whether the Verse:-- "This day I have perfected your religion for you." was revealed on a Friday or not.