Sahih Muslim 3017a

Tariq b. Shihab reported that a Jew said to'Umar: You recite a verse which, if it had been revealed in relation to us, we would have taken that day as the day of rejoicing. Thereupon 'Umar said: I know where it was revealed and on the day when it was revealed and where Messenger of Allah ﷺ had been at that time when it was revealed. It was revealed on the day of 'Arafa (ninth of Dhu'l Hijjah) and Messenger of Allah ﷺ had been staying in 'Arafat. Sufyan said: I doubt, whether it was Friday or not (and the verse referred to) is this:" Today I have perfected your religion for you and completed My favours upon you" (v. 4).

حَدَّثَنِي أَبُو خَيْثَمَةَ، زُهَيْرُ بْنُ حَرْبٍ وَمُحَمَّدُ بْنُ الْمُثَنَّى - وَاللَّفْظُ لاِبْنِ الْمُثَنَّى - قَالاَ حَدَّثَنَا عَبْدُ الرَّحْمَنِ، - وَهُوَ ابْنُ مَهْدِيٍّ - حَدَّثَنَا سُفْيَانُ، عَنْ قَيْسِ بْنِ مُسْلِمٍ، عَنْ طَارِقِ، بْنِ شِهَابٍ أَنَّ الْيَهُودَ، قَالُوا لِعُمَرَ إِنَّكُمْ تَقْرَءُونَ آيَةً لَوْ أُنْزِلَتْ فِينَا لاَتَّخَذْنَا ذَلِكَ الْيَوْمَ عِيدًا . فَقَالَ عُمَرُ إِنِّي لأَعْلَمُ حَيْثُ أُنْزِلَتْ وَأَىَّ يَوْمٍ أُنْزِلَتْ وَأَيْنَ رَسُولُ اللَّهِ ﷺ حَيْثُ أُنْزِلَتْ أُنْزِلَتْ بِعَرَفَةَ وَرَسُولُ اللَّهِ ﷺ وَاقِفٌ بِعَرَفَةَ . قَالَ سُفْيَانُ أَشُكُّ كَانَ يَوْمَ جُمُعَةٍ أَمْ لاَ . يَعْنِي { الْيَوْمَ أَكْمَلْتُ لَكُمْ دِينَكُمْ وَأَتْمَمْتُ عَلَيْكُمْ نِعْمَتِي}