Apart from ignoring the points I made about "brothers here is more of what you are ignoring.
Mary the Mother of God
It is worth pointing out at the start that this title is not peculiar to Catholicism. The Orthodox also believe this, as do Anglicans (and therefore probably Episcopalians) and Lutherans.
"The Holy Virgin is the Mother of God (Theotokos) since according to the flesh she brought forth the Word of God made flesh" (Council of Ephesus, 431 AD)
“What the Catholic faith believes about Mary is based on what it believes about Christ, and what it teaches about Mary illumines in turn its faith in Christ.” (Catechism of the Catholic Church, para 487)
Let us therefore start with Jesus. The early centuries of Christianity were marked by controversies over the nature of Jesus Christ. Was he God? Was he man? Was he born human and became God?
The definition of Mary as
Theotokos (literally “God bearer”) at the Council of Ephesus in 431 was made in response to a fifth century heresy called Nestorianism which said that Mary did not carry God but only carried Christ’s human
nature in her womb.
Nestorians claimed that Mary did not give birth to a unified person but tried to separate Jesus’ human nature from his divine nature, creating two separate persons, one human and one divine in a loose affiliation.
But a woman carries a
person in her womb, not just a human
nature. Mary carried, and gave birth to, the
person of Jesus Christ, and that
person was God, the second person of the Trinity.
This does not mean Mary is older than God, or that she is the source of her Son’s divinity. She is the Mother of God in that she carried in her womb, and gave birth to, a divine person – Jesus Christ, God “in the flesh”
The definition of Ephesus was not to glorify Mary but to affirm that Jesus’ two natures – divine and human were united in one divine
person.
If we do not accept that what Jesus did and experienced in his humanity was experienced by God (the Son) then we cannot say that God died on the cross and we are not redeemed; we cannot say that God shed his blood for us and our sins are not forgiven.
The logic is:
Jesus is God
Mary is the mother of Jesus
Therefore Mary is the mother of God
Scripture Summary
Jesus is God
Jesus Christ is the Word, the second person of the Trinity.
“In the beginning was the Word, and the Word was with God, and the
Word was God.” (
Jn 1:1)
Mary is the mother of Jesus
He assumed human nature (came in the flesh)
“And the
Word became flesh and dwelt among us” (
Jn 1:14)
Where did the Word become flesh? In the womb of Mary
“And behold,
you will conceive in your womb and
bear a son, and you shall call his name Jesus.” (
Lk 1:31).
“God sent his Son,
born of a woman, born under the law” (
Gal 4:4).
Mary was the mother of that son. The Word that became flesh, the second Person of the Trinity in human form, though still divine.
“who, though he was in the form of God, did not count equality with God a thing to be grasped, but emptied himself, taking the form of a servant, being born in the likeness of men. And being found in human form he humbled himself and became obedient unto death, even death on a cross.” (
Phil 2:6-8)
Therefore Mary is the mother of God
In
Lk 1:43 Elizabeth says (while “filled with the Holy Spirit”) And why is this granted me, that the mother of my Lord (
kuriou) should come to me? Several times in chapter 1 Luke uses kurios for God (indeed Mary herself does in verse 38). So Elizabeth calling Mary The mother of my Lord is calling her the mother of my God.
Early Christian witness
The early Church Fathers recognised Mary as the Mother of God. Here are a few quotes from them:
"The Virgin Mary, being obedient to his word, received from an angel the glad tidings that she would bear God" (Iranaeus -
Against Heresies, 5:19:1 [A.D. 189]).
"[T]o all generations they [the prophets] have pictured forth the grandest subjects for contemplation and for action. Thus, too, they preached of the advent of God in the flesh to the world, his advent by the spotless and God-bearing (theotokos) Mary in the way of birth and growth, and the manner of his life and conversation with men, and his manifestation by baptism, and the new birth that was to be to all men, and the regeneration by the laver [of baptism]" (Hippolytus -
Discourse on the End of the World 1 [A.D. 217]).
"For Luke, in the inspired Gospel narratives, delivers a testimony not to Joseph only, but also to Mary the Mother of God, and gives this account with reference to the very family and house of David" (Gregory the Wonderworker
Four Homilies 1; 262 AD).
"(Those engaged in the public transport service) came to the church of the most blessed Mother of God, and Ever-Virgin Mary, which, as we began to say, he had constructed in the western quarter, in a suburb, for a cemetery of the martyrs" (Peter of Alexandria
The Genuine Acts of Peter of Alexandria; 305 AD).
"While the old man [Simeon] was thus exultant, and rejoicing with exceeding great and holy joy, that which had before been spoken of in a figure by the prophet Isaiah, the holy Mother of God now manifestly fulfilled" (Methodius
Oration on Simeon and Anna 7; 305 AD).
"We acknowledge the resurrection of the dead, of which Jesus Christ our Lord became the firstling; he bore a body not in appearance but in truth derived from Mary the Mother of God" (Alexander of Alexandria
Letter to All Non-Egyptian Bishops 12; 324 AD).
"The Father bears witness from heaven to his Son. The Holy Spirit bears witness, coming down bodily in the form of a dove. The Archangel Gabriel bears witness, bringing the good tidings to Mary. The Virgin Mother of God bears witness" (Cyril of Jerusalem
Catechetical Lectures 10:19; 350 AD).
"Though still a virgin she carried a child in her womb, and the handmaid and work of his wisdom became the Mother of God" (Ephraim the Syrian
Songs of Praise 1:20; 351 AD).
"The Word begotten of the Father from on high, inexpressibly, inexplicably, incomprehensibly, and eternally, is he that is born in time here below of the Virgin Mary, the Mother of God" (Athanasius
The Incarnation of the Word of God 8; 365 AD).
"Being perfect at the side of the Father and incarnate among us, not in appearance but in truth, he [the Son] reshaped man to perfection in himself from Mary the Mother of God through the Holy Spirit" (Epiphanius of Salamis
The Man Well-Anchored 75; 374 AD).
"The first thing which kindles ardor in learning is the greatness of the teacher. What is greater than the Mother of God? What more glorious than she whom Glory Itself chose?" (Ambrose of Milan
The Virgins 2:2[7]; 377 AD).
This Virgin became a Mother while preserving her virginity;
And though still a Virgin she carried a Child in her womb;
And the handmaid and work of His Wisdom
became the Mother of God
(St Ephraim,
Songs of Praise, 1, 20; c. 381 AD)
"If anyone does not agree that Holy Mary is Mother of God, he is at odds with the Godhead" (Gregory of Nazianz
Letter to Cledonius the Priest 101; 382 AD).