Advent prepared us for the coming of the saviour, the fulfillment of the promise first made in the Garden of Eden in response to the sin of Adam & Eve. Christmas is the day we celebrate that hope fulfilled. Jesus is the only hope of the world, because Jesus is the only one who could set us free from our sins. The commemoration of the nativity of Our Lord puts before us once again the story of the long-awaited King who left His heavenly home to enter time and become human like us. When God wante4d to save you from your sins, He did not send a prophet or even an angel; He sent His own Son into human flesh just like ours.
The exact date of the birth of Jesus is not known, and during the earliest centuries of the Church it seemed to have little significance. This followed the Early Church’s tradition of honouring and celebrating a Christians death as his or her birth date into eternity and the ongoing presence of Jesus. Likewise, the life, work, death & resurrection of Christ was of much greater importance to early Christians than the earthly details of His life. The earliest nativity feast, Epiphany (January 6), celebrated both the birth and Baptism of Christ. However, in the fourth century great Christological controversies that questioned Christ’s divinity raced throughout Christianity. By AD 336, December 25 had been established in Rome as the celebration of Christ’s birth, a festival welcomed particularly by orthodox Christians from the West. From Rome, Christs natal festival spread throughout the Western Church. In Eastern traditions of the Church, Epiphany remains the principal celebration of the birth of Jesus.
Extracted from - Treasury of Daily Prayer, p. 1051, 1054