I den tradisjonelle liturgien leser vi i Matutus 4., 5. og 6. lesning:
From the Sermons of Pope St Leo the Great – 7th for Christmas.
Dearly beloved brethren, whosoever will keep truly and honour piously this day’s festival, it is necessary for him neither to think falsely of the Lord’s Incarnation, nor meanly of the Lord’s Godhead. For as there is danger, on the one hand, of denying the truth of Christ’s participation of our nature, so is there no less danger, on the other, of doing despite to the equality of His glory with the glory of the Father. Wherefore, when we draw near to understand the mystery of Christ’s Birth, wherein He was born of the Virgin Mary, we must leave the clouds of earthly imagination behind and pierce the fog of human wisdom with the eye of enlightened faith.
The authority on which we believe is the authority of God Himself; the teaching which we follow is the teaching of God Himself. Wherefore whether we lend the ear of our mind to the testimony of the Law, or to the revelations of the Prophets, or to the full pealing of the Gospel trumpet, that is true, which John the Son of Thunder, uttered, when he was filled with the Holy Ghost, and said In the beginning was the Word, and the Word was with God, and the Word was God. The Same was in the beginning with God. All things were made by Him, and without Him was not anything made. True also is his witness when he saith The Word was made Flesh, and dwelt among us, and we beheld His glory, the glory as of the Only-begotten of the Father. John i. 1-3, 14.
The Person of the Son of God therefore remaineth unchanged and one, though He have two natures, keeping His own, and taking ours. He appeareth as man to be the restorer of men, but abideth all the while in His immutable Godhead. That Godhead which He shareth with the Father was not a whit the less Almighty, nor did the form of a servant touch the form of God to derogate from it. The Most High and Everlasting Being, bending down for man’s salvation, took the Manhood into His glory; He ceased not to be That which He is from everlasting. Hence we see the Only-begotten Son of God in one place confessing that the Father is greater than He, John xiv. 28, and in another declaring that He and the Father are One, x. 30. This is an evident proof of the distinction of His two natures, and the unity of His Person; for He is inferior to the Father as touching His Manhood, and yet equal to the Father as touching His Godhead, and yet, though He be God and Man, He is not two, but One Christ.