Tariq bin Shihab says: A person belonging to the Jews said to Sayyiduna Umar (may Allah be pleased with him): If this verse had been revealed to us, "This day I have perfected for you your religion and completed My favor upon you and have approved for you Islam as religion." (5-al-Ma'idah:13), we would have declared that day as a day of Eid. So Sayyiduna Umar (may Allah be pleased with him) said: I know on which day this verse was revealed. This verse was revealed on the day of Arafah and it was revealed on a Friday.