For the birth of Christ is the origin of the people of Christ, and the birthday of the head is the birthday of the body. It is true that each of those who are called is allotted a particular place, and that all the sons of the Church are separated from each other by intervals of time. However, just as all the faithful together, born of the waters of baptism, are crucified with Christ in his passion, raised with him in his resurrection, and given a place with him at the Father’s right hand in his ascension, so too, with him they are born in this his birth.
Throughout the world, every one of the faithful is reborn in Christ, and leaving the path of his old origins passes by rebirth into a new man. No longer is he reckoned among his human father’s stock but among the seed of the Saviour, who became the Son of man in order that we might have the power to be the sons of God.
St. Leo the Great
Sermon 6 On the Nativity
