37 In St. Leo's view, this remarkable unity of the Church has its well-spring in the birth of God's Incarnate Word. "For Christ's birth is the source of life for Christian people; the birthday of the Head is the birthday of the Body. Although every individual is called in his own turn, and all the Church's sons are separated from one another by intervals of time, yet the entire body of the faithful, born in the baptismal font, is born with Christ in His nativity, just as all are crucified with Him in His passion, raised again in His resurrection, and set at the Father's right hand in His ascension." (27)
Source: Aeterna Dei Sapientia (Vatican.va)