Sahih Bukhari

Once a Jew said to me, "O the chief of believers! There is a verse inyour Holy Book Which is read by all of you (Muslims), and had it beenrevealed to us, we would have taken that day (on which it was revealedas a day of celebration." 'Umar bin Al-Khattab asked, "Which is thatverse?" The Jew replied, "This day I have perfected your religion Foryou, completed My favor upon you, And have chosen for you Islam asyour religion." (5:3) 'Umar replied,"No doubt, we know when and wherethis verse was revealed to the Prophet. It was Friday and the Prophet (ﷺ)was standing at 'Arafat (i.e. the Day of Hajj)"