It was narrated that Tariq bin Shihab said: A Jew said to `Umar: "If this Verse had been revealed to us, we would have taken it as a festival (Eid): 'This day, I have perfected your religion for you.'" Umar said: "I know the day when it was revealed and the night on which it was revealed: a Friday night when we were with Messenger of Allah in Arafat."
Source: sunnah.com
Other translations
Arabic
أَخْبَرَنَا إِسْحَاقُ بْنُ إِبْرَاهِيمَ، قَالَ أَنْبَأَنَا عَبْدُ اللَّهِ بْنُ إِدْرِيسَ، عَنْ أَبِيهِ، عَنْ قَيْسِ بْنِ مُسْلِمٍ، عَنْ طَارِقِ بْنِ شِهَابٍ، قَالَ قَالَ يَهُودِيٌّ لِعُمَرَ لَوْ عَلَيْنَا نَزَلَتْ هَذِهِ الآيَةُ لاَتَّخَذْنَاهُ عِيدًا { الْيَوْمَ أَكْمَلْتُ لَكُمْ دِينَكُمْ } قَالَ عُمَرُ قَدْ عَلِمْتُ الْيَوْمَ الَّذِي أُنْزِلَتْ فِيهِ وَاللَّيْلَةَ الَّتِي أُنْزِلَتْ لَيْلَةَ الْجُمُعَةِ وَنَحْنُ مَعَ رَسُولِ اللَّهِ صلى الله عليه وسلم بِعَرَفَاتٍ .
sunnah.com