The Solemnity of “Holy Mary, Mother of God” is the oldest that is known in the West.
The Christians of Egypt, according to a third century testimony, addressed Mary with this prayer: “We fly to thy patronage, O holy Mother of God; despise not our petitions in our necessities, but deliver us always from all dangers, O glorious and blessed Virgin.”
In the fourth century the term “Theotokos,” meaning Mother of God, was used frequently in both the East and the West. However, in the fifth century, the heretic Nestorius dared to say that Mary was not the Mother of God. He did not admit the unity of Christ’s person and erroneously interpreted the distinction between the two natures - divine and human. The bishops united in the Council of Ephesus (431 A.D.) affirmed the subsistence of the divine nature and the human nature in the one person of the Son. They declared at the same time: “The Virgin Mary is the Mother of God, because her Son, Christ, is God.” This declaration was followed by a procession, in which they carried lighted torches and sang, “Holy Mary, Mother of God, pray for us sinners now and at the hour of our death. Amen.”
The Catechism of the Catholic Church in number 509 says, “Mary is truly ‘Mother of God’ since she is the mother of the eternal Son of God made man, who is God himself.”
Saint John Paul II, speaking about title Mary, Mother of God in November of 1996, said that, “The expression Theotokos, which literally means, ‘she who has begotten God,’ can at first sight seem surprising; in fact, it raises the question as to how it is possible for a human creature to give birth to God. The answer of the Church's faith is clear: Mary's divine motherhood refers only to the human begetting of the Son of God but not, however, to his divine birth.” He then added, “The Son of God was eternally begotten of God the Father, and is consubstantial with him. Mary, of course, has no part in this eternal birth. However, the Son of God assumed our human nature 2,000 years ago and was conceived by and born of Mary” (General Audience, November 27, 1996).
What meaning does this feast have for us? We can remember Mary as not only the Mother of God, but also as our Mother. From the cross, Jesus gave us his Mother; He gave her to us so that we would welcome her. It is amazing that Jesus would give us such a gift. Our reaction should be like that of Elizabeth: “And how does this happen to me, that the mother of my Lord should come to me?” (Lk 1:43). Full of amazement, we can only give thanks to God and address Mary with childlike confidence. We entrust all our needs, petitions, and worries to her. She prays for us and teaches us to abandon ourselves with her to God’s will.