It was mentioned by Abu Dawud on the authority of Ibn Umar that the Messenger of God, may God bless him and grant him peace, stood between the Jamarat on the Day of Sacrifice during the Hajj on which he performed Hajj and said, “What day is this?” They said, “This is the Day of Sacrifice,” and he said, “This is the day of the Greater Hajj.”

It means what God called it in His saying, “And a call to prayer from God and His Messenger to the people on the day of the Greater Hajj.”