The Divine Maternity of Mary
Holy Scripture tells us that those who first came to adore Him Who is Son of God and Son of Mary found Him "with Mary his Mother." At the scene of the first miracle at Cana, which marked the opening of his public life, "the Mother of Jesus was there." In the tremendous hour when all was consummated, when types and shadows gave place to the mighty reality, "there stood by the Cross of Jesus His Mother." And when the little flock who were to be the nucleus of the Church of God awaited in prayer the coming of the Paraclete, Who would teach them all truth, again it was in company with "Mary the Mother of Jesus." Far from taking from the honor and love due to the Word Incarnate, devotion to Mary is a strong bulwark protecting the central doctrine. He is ever found with His Mother; where Mary is denied her rights, sooner or later Jesus is denied His; they stand or fall together.
This was realized in the year 431 when, at the General Council of Ephesus, the Church condemned the Nestorian heresy, whereby the Patriarch of Constantinople, Nestorius, had taught that, since in Christ there are two persons, a Divine and a human, Mary was mother only of the Man "Christ", and therefore could not be called "Mother of God." He therefore denied "that wondrous and substantial union of the two natures which we call hypostatic."
On the occasion of the fifteenth centenary of the Council of Ephesus, the Sovereign Pontiff, Pius XI, issued the Encyclical Lux Veritatis, recalling the history of the heresy and commenting thus upon the dogma of the hypostatic union: "When once the doctrine of the hypostatic union is abandoned, whereon the dogmas of the Incarnation and of man's Redemption rest and stand firm, the whole foundation of the Catholic religion falls and comes to ruin. ...When once this dogma of the truth is securely established, it is easy to gather from it that, by the mystery of the Incarnation, the whole aggregate of men and of mundane things has been endowed with a dignity than which certainly nothing greater can be imagined, and surely grander than that to which it was raised by the work of creation."
Proceeding to speak of the special dignity of the Blessed Virgin Mary, the Pope emphasizes that, "because she brought forth the Redeemer of mankind, she is also in a manner the most tender Mother of us all, whom Christ our Lord deigned to have as His brothers; wherefore we may confidently entrust to her all things that are ours, our joys, our troubles, our hopes; especially if more difficult times fall upon the Church — if faith fail because charity has grown cold, if private and public morals take a turn for the worse."
Desirous "to mark the commemoration, and help to nourish the piety of clergy and people towards the great Mother of God," His Holiness concludes the Encyclical by establishing the new feast of the Divine Motherhood, to be celebrated on October 11 by the universal Church.