The Most-Holy Mother of God, must be considered to be part of Orthodox Dogmatical teachings, because through her, our Lord Jesus Christ was Incarnate, in other words took human flesh from her, that He might not only restore human nature to its original state, but that He might also unite it with the Holy Trinity in His Person, in order to also Deify our humanity. Secondly, the Mother of God is important in dogmatic theology for in her the necessary free response of humanity to God is embodied. She is the first to receive full salvation and in her all humanity is given the opportunity to become God-bearers. Thus, in the Mother of God the Divine initiative and human response necessary for salvation, meet. 

The Holy Mother of God often throughout the centuries, became a reason for debate between the ill-intended heretics who uttered their disrespectful and impious theories, which the Holy Fathers of the Church, fought angainst, rejected and condemned through the convening of Holy Ecumenical Councils.  During the First Ecumenical Council at Nicea the Holy Fathers affirmed in the Holy Creed, the purity of the Holy Mother, and thus stated in the Fourth Article: “who for us men and for our salvation became man and was incarnate of the Holy Spirit and the Virgin Mary.” 

At the Third Ecumenical Council at Ephesus, the Holy Fathers defended the use of the term “Theotokos” (which means Birthgiver of God or Mother of God) in honouring her, because He who was born of her was the Son of God, who united in His Person both Divine and human natures.
 

During the Fourth Ecumenical Council at Chalcedon, the Holy Fathers spoke of her as both 'Virgin' and 'Mother of God': “. . . we unanimously proclaim that we should confess one and the same Son, our Lord Jesus Christ, perfect in deity and perfect in humanity, . . . born of the Father before all the worlds in His deity, born in these last times of Mary the Virgin, Mother of God, in His humanity, one and the same Christ, Son, Lord, only-Begotten, who was made known in two natures without being mingled, without change, indivisibly, . . .”

Finally, at the Fifth Ecumenical Council in 553, the Holy Fathers affirmed the Dogma of the Perpetual Virginity of the Holy Mother of God, by endorsing the term ‘Ever-Virgin,’ as a Dogmatical Truth of our Holy Faith.