East: Bishop St. Ignatius the Martyr of Antioch says in 107 [Letter to the Ephesians 7 in PG 5:652A], "There is one Physician who is possessed both of flesh and spirit; both made and not made; God existing in flesh; true life in death; both of Mary and of God; first passible and then impassible—even Jesus Christ our Lord." Mary gave birth to God.
West: Bishop St. Irenaeus of Lyons says in 189 [Against Heresies 5:19:1 in PG 7B:1175B], "The Virgin Mary, being obedient to his word, received from an angel the glad tidings that she would bear God." The Blessed Virgin Mary is thus the Θεοτόκος, which means the Bearer of God.
East: Bishop St. Gregory the Wonderworker of Neocaesarea says in 262 [Homily 1 On the Annunciation to the Holy Virgin Mary in PG 10:1153B], "For Luke, in the inspired Gospel narratives, delivers a testimony not to Joseph only, but also to Mary, the Mother of God, and gives this account with reference to the very family and house of David." The same great bishop, to whom the Mother of God herself appeared, adds [Homily 2 On the Annunciation to the Holy Virgin Mary in PG 10:1156B], "It is our duty to present to God, like sacrifices, all the festivals and hymnal celebrations; and first of all, [the feast of] the Annunciation to the holy Mother of God, to wit, the salutation made to her by the angel, 'Hail, full of grace!'"
East: Bishop St. Methodius the Martyr of Olympus says in 305 [Oration on Simeon and Anna 7 in PG 18:364A], "While the old man [St. Simeon] was thus exultant, and rejoicing with exceeding great and holy joy, that which had before been spoken of in a figure by the prophet Isaiah, the holy Mother of God now manifestly fulfilled." In n. 14 of the same oration [PG 18:382ABC], the illustrious martyr and great hierarch adds,
Hail to you forever, you virgin Mother of God, our unceasing joy, for unto you do I again return. ... Hail, you fount of the Son's love for man. ... Wherefore, we pray you, the most excellent among women, who boast in the confidence of your maternal honors, that you would unceasingly keep us in remembrance. O holy Mother of God, remember us, I say, who make our boast in you, and who in august hymns celebrate your memory, which will ever live, and never fade away.East: Patriarch St. Alexander of Alexandria says in 324 [Letter to Bishop Alexander of Constantinople 12 in PG 18:568CD],
After this, we receive the doctrine of the resurrection from the dead, of which Jesus Christ our Lord became the first-fruits; Who bore a Body, in truth, not in semblance, derived from Mary the Mother of God in the fullness of time sojourning among the race, for the remission of sins: Who was crucified and died, yet for all this suffered no diminution of His Godhead.East: Patriarch St. Cyril of Jerusalem (Doctor) says in 350 [Catechetical Lectures 10:19 in PG 33:685A], "The Father bears witness from Heaven to His Son. The Holy Spirit bears witness, coming down bodily in the form of a dove. The archangel Gabriel bears witness, bringing the good tidings to Mary. The Virgin Mother of God bears witness."
East: Patriarch St. Athanasius I the Great of Alexandria (Doctor) says in 362 [Orations 3:14 in PG 26:349C], "And the Angel on his appearance, himself confesses that he has been sent by his Lord; as Gabriel confessed in the case of Zacharias, and also in the case of Mary, bearer of God."
East: Bishop St. Gregory of Nyssa says in 377 [On Virginity 13 in PG 46:377D], "Just as, in the age of Mary the Mother of God, He who had reigned from Adam to her time found..."
West: Bishop St. Ambrose the Great of Milan (Doctor) says in 377 [Concerning Virginity 2:2:7 in PL 16:209A], "The first thing which kindles ardor in learning is the greatness of the teacher. What is greater than the Mother of God? What more glorious than she whom Glory Itself chose?"
East: Patriarch St. Gregory I the Theologian of Nazianzus (Doctor) says in 382 [Epistle 101 To Cledonius the Priest Against Apollinarius in PG 37:177C], "If anyone does not believe that holy Mary is the Mother of God, he is severed from the Godhead."
West: Hieromonk St. Jerome the Great of Strido (Doctor) says in 401 [Apology Against Rufinus 2:10 in PL 23:452A], "As to how a virgin became the Mother of God, he has full knowledge; as to how he himself was born he knows nothing."
East: Patriarch St. Cyril I of Alexandria (Doctor of the Incarnation) says in 427 [Letter 1 To the Monks of Egypt in PG 77:13B], "I have been amazed that some are utterly in doubt as to whether or not the holy Virgin is able to be called the Mother of God. For if our Lord Jesus Christ is God, how should the holy Virgin who bore Him not be the Mother of God?" The same great pillar of the faith explains this in greater detail in Letter 4, his second epistle to Nestorius [PG 77:48D-49A]:
This expression, however, "the Word was made flesh" [John 1:14], can mean nothing else but that He partook of flesh and blood like to us; He made our body His own, and came forth man from a woman, not casting off His existence as God, or His generation of God the Father, but even in taking to Himself flesh remaining what He was. This the declaration of the correct faith proclaims everywhere. This was the sentiment of the holy Fathers; therefore they ventured to call the holy Virgin "the Mother of God," not as if the nature of the Word or His divinity had its beginning from the holy Virgin, but because of her was born that holy body with a rational soul, to which the Word, being personally united, is said to be born according to the flesh.West:
Notes & References
The statement in Discourse on the End of the World 1 [PG 10:905A] calling our Lady "the spotless and God-bearing Mary" is from Pseudo-Hippolytus.