To understand the title, “Mother of God,” we must first clearly understand Mary’s role as mother of our Savior, Jesus Christ. As Catholics, we firmly believe in the incarnation of our Lord: Mary conceived by the power of the Holy Spirit. (Confer Luke 1:26-38 and Matthew 1:18-25.)
Through her, Jesus Christ– second person of the Holy Trinity, one-in-being (consubstantial) with the Father, and true God from true God– entered this world taking on human flesh and a human soul. Jesus is true God and true man. In His person are united both a divine nature and a human nature. Mary did not create the divine person of Jesus, who existed with the Father from all eternity: “In fact, the One whom she conceived as man by the Holy Spirit, who truly became her Son according to the flesh, was none other than the Father’s eternal Son, the second person of the Holy Trinity.
Hence the Church confesses that Mary is truly ‘Mother of God’ (Theotokos)” (Catechism, #495). As St. John wrote, “The Word became flesh and made His dwelling among us, and we have seen His glory: The glory of an only Son coming from the Father filled with enduring love” (John 1:14).
“Hail Mary, Full of Grace, The Lord is with thee. Blessed art thou among women, and blessed is the fruit of thy womb, Jesus. Holy Mary, Mother of God, pray for us sinners now, and at the hour of our death. Amen.”