The veneration we have for Mary Mother of God comes straight from Scripture. When Elizabeth saw the Blessed Virgin she “was filled with the Holy Spirit and cried out in a loud voice…”Who am I that the Mother of my Lord should come to me?”
Elizabeth’s “Lord” of course is Jawheh–the Lord God Almighty. Elizabeth therefore not only calls Mary the “Mother of the Lord God” but she does so through the direct inspiration of the Holy Spirit. The title “Mother of God” ratified by the church as a defense of the divinity of Christ is therefore based firmly in Scripture, and firmly by inspiration from the Holy Spirit himself.
Why then do non-Catholic Christians object to this title? Probably because they misunderstand it, but also because they very often misunderstand or (unknowingly) hold a heretical understanding of the incarnation. This is why the title “Mother of God” was from the beginning not so much an honor to the Blessed Virgin, but an honor to her son.
Read More: Mother of God–Defender of Orthodoxy