Mary the mother of God
Jesus is God - and His mother was Mary – so she is the mother of God.
Elizabeth calls her the mother of her Lord (meaning God):
Luke 1:42,43 ... 'Blessed are you among women, and blessed is the fruit of your womb. And why has this happened to me, that the mother of my Lord comes to me?'
Also, an angel of the Lord spoke to Joseph in a dream:
Matthew 1:20-23 'But just when he had resolved to do this, an angel of the Lord appeared to him in a dream and said, 'Joseph, son of David, do not be afraid to take Mary as your wife, for the child conceived in her is from the Holy Spirit. She will bear a son, and you are to name him Jesus, for he will save his people from their sins.' All this took place to fulfil what had been spoken by the Lord through the prophet: 'Look, the virgin shall conceive and bear a son, and they shall name him Emmanuel', which means, 'God is with us.''
While confirming that God will be the Father of Jesus, the angel also insists that the child Mary will bear will be called ‘God with us’.
While it is recognised that the ‘divine nature’ of Jesus came from God and the ‘human nature’ came from Mary, Mary didn’t give birth to a ‘human nature’, but to a person – and that person was Jesus, the third person of the Holy Trinity. There is no suggestion or claim that Mary somehow is the origin of God, but only a created woman who was specially blessed.
Mary is not God, nor is she the origin of God, but a woman who herself needed a saviour. Mary’s sinlessness did not mean that she did not need Christ as her Saviour (as she herself proclaimed):
Luke 1:46 'And Mary said, 'My soul magnifies the Lord, and my spirit rejoices in God my Saviour, for he has looked with favour on the lowliness of his servant.'
Ecumenical discussions have also clarified this description of Mary as the Mother of God:
“The Final report from the dialogue between the Pentecostal Church and the Catholic Church at the World Council of Churches exchanges between 1977-1982 (p.729)
This report concluded that:
“Both Roman Catholics and Pentecostals agree that Mary is the Mother of Jesus Christ, who is the Son of God, and as such she occupies a unique place. Both Roman Catholics and classical Pentecostals recognise the historical origins of the title “Mother of God” (theotokos) arising from the christological disputes at the council of Ephesus (AD 431). In order to preserve the unity of the one person having two natures to which the Virgin gave birth, the council approved the title “theotokos”(“God-bearer” or “Mother of God”). This was not a Marian definition, concerned to give Mary a new title, but a Christological definition concerned with the identity of Jesus Christ. It is only at the moment of the incarnation that she becomes the mother of God. She is not the Mother of God in his eternal triune existence, but the Mother of God in his incarnation.”Growth in Agreement II – World Council of Churches (p.729)