The Son of God is the first-born of many brothers. Although by nature he is the only-begotten, by grace he has joined many to himself and made them one with him. For to those who receive him he has given the power to become the sons of God. He became the Son of man and made many men sons of God, uniting them to himself by his love and power, so that they became as one. In themselves they are many by reason of their human descent, but in him they are one by divine rebirth. The whole Christ and the unique Christ—the body and the head—are one: one because born of the same God in heaven, and of the same mother on earth. They are many sons, yet one son. Head and members are one son, yet many sons; in the same way, Mary and the Church are one mother, yet more than one mother; one virgin, yet more than one virgin. Both are mothers, both are virgins. Each conceives of the same Spirit, without concupiscence. Each gives birth to a child of God the Father, without sin. Without any sin, Mary gave birth to Christ the head for the sake of his body. By the forgiveness of every sin, the Church gave birth to the body, for the sake of its head. Each is Christ’s mother, but neither gives birth to the whole Christ without the cooperation of the other.