Of this mystery the first manifestation to the world was the birth of our Lord at Bethlehem. Whence we see the reason why every year at Christmas the Church says "Puer natus est nobis et Filius datus est nobis" - Unto us a Child is born, unto us a Son is given - It is the Son of God, God begotten of the Father in the one day of eternity (Ego hodie genui te), who is now begotten of the Father as Man in the day of the Incarnation: Ego hodie genui te. " By the taking of the Manhood into God," says St. Athanasius, the Son of Mary is born to the divine Life. As it was at midnight that our Lady brought her first-born Son into the world and laid Him in a cradle, so Mass is celebrated at midnight in St. Mary Major, where the relics of the crib are kept.
"With great devotion," says St. Leo, "has the Incarnate Word given Himself to win for us the fight against Satan, for not in His divine Majesty but in the weakness of our flesh He waged war against this cruel enemy"."The victory which He has gained, in spite of His weakness, shows Him to be God. It is God of God, Light of Light," (Credo) who disperses the darkness of sin. "Christ is the true Light who comes to enlighten the world, plunged in darkness" (Collect). "By the mystery of the Word made Flesh," says the Preface, "the light of Thy glory hath shone anew upon the eyes of our mind: so that while we acknowledge Him as God seen by men, we may be drawn by Him to the love of things unseen." "The grace of God our Saviour hath appeared to all men, instructing us to deny ungodliness and worldly desires ... that He might redeem us from all iniquity, and might cleanse to Himself a people acceptable, and zealous in good works." (Epistle). He is made like unto us that we may become like unto Him (Secret), and by His example may be enabled to live a holy life (Postcommunion). Thus shall we "live soberly, justly, and godly in this world, looking for the blessed hope and coming of the glory of the great God and our Saviour Jesus Christ " (Epistle).
As we saw in Advent, the first Coming of our Lord prepares us for the second.
(Chapel of the Nativity, Bethlehem)
Dominus dixit ad me: Filius meus es tu, ego hodie genui te. * Quare fremuerunt gentes: et populi meditati sunt inania?
The Lord hath said to me: Thou art My Son, this day have I begotten Thee. * Why have the Gentiles raged, and the people devised vain things?
(Psalm 2:7,1 from the Introit of Mass)
At that time, there went out a decree from Caesar Augustus, that the whole world should be enrolled. This enrolling was first made by Cyrinus, the governor of Syria. And all went to be enrolled, every one into his own city. And Joseph also went up from Galilee, out of the city of Nazareth, into Judea, to the city of David, which is called Bethlehem; because he was of the house and family of David, to be enrolled with Mary, his espoused wife, who was with child. And it came to pass, that when they were there, her days were accomplished that she should be delivered. And she brought forth her first born Son, and wrapt him up in swaddling-clothes, and laid him in a manger; because there was no room for them in the inn. And there were in the same country Shepherds watching and keeping the night-watches over their flock. And behold an Angel of the Lord stood by them, and the brightness of God shone round about them, and they feared with a great fear. And the Angel said to them: Fear not: for behold I bring you good tidings of great joy, that shall be to all the people: for this day is born to you a Saviour, who is Christ the Lord, in the city of David. And this shall be a sign unto you: You shall find the Infant wrapped in swaddling-clothes, and laid in a manger. And suddenly there was with the Angel a multitude of the heavenly army, praising God and saying: Glory to God in the highest; and on earth peace to men of good will.