Theotokos: The Mother of God in Scripture

In the sixth month the angel Gabriel was sent from God to a city of Galilee named Nazareth, to a virgin betrothed to a man whose name was Joseph, of the house of David; and the virgin's name was Mary. And he came to her and said, "Hail, full of grace, the Lord is with you!" But she was greatly troubled at the saying, and considered in her mind what sort of greeting this might be.  And the angel said to her, "Do not be afraid, Mary, for you have found favor with God.  And behold, you will conceive in your womb and bear a son, and you shall call his name Jesus.  He will be great, and will be called the Son of the Most High; and the Lord God will give to him the throne of his father David, and he will reign over the house of Jacob for ever; and of his kingdom there will be no end."  And Mary said to the angel, "How shall this be, since I have no husband?"  And the angel said to her, "The Holy Spirit will come upon you, and the power of the Most High will overshadow you; therefore the child to be born will be called holy, the Son of God.  And behold, your kinswoman Elizabeth in her old age has also conceived a son; and this is the sixth month with her who was called barren.  For with God nothing will be impossible."  And Mary said, "Behold, I am the handmaid of the Lord; let it be to me according to your word." And the angel departed from her.

Luke 1:26-38

The term “mother of God” is not expressly found in the Bible.  Mary is referred to as “the mother of Jesus” (John 2:1;  19:26) or “mother of the Lord” (Luke 1:43).  However since Jesus Christ is true God, all references to Mary as His mother show her divine motherhood.  

This is reinforced by the way Scripture refers to Joseph only as the foster-father of Jesus (Matt 1:25; Luke 1:34 ff; 3:23) but attributes all the ordinary functions of maternity to Mary – conception, gestation, and parturition (Matt 1:18 ff; Luke 2:5 ff).

The motherhood was foretold by Isaiah, “Behold, a virgin shall conceive, and bear a son, and his name shall be called Emmanuel, God with us (Is 7:14).  The Archangel Gabriel echoed these words at  the Annunciation, “And behold, you will conceive in your womb and bear a son, and you shall call his name Jesus” (Luke 1:31).   

Further the angel announces, “therefore the child to be born will be called holy, the Son of God”(Luke 1:35).  Because Mary bore the Son of God, she is then truly the mother of God.  St. Paul writes to the Galatians, “But when the time had fully come, God sent forth his Son, born of woman” (Gal 4:4).  If the man Jesus, “born of a woman”,  is the Son of God, then that “woman” must be the mother of a Divine Son, and consequently, the mother of God (Rom 9:5).