Can we say God died? Just as much as we can say God was born and called God with us...
The Nestorian Heresy
The Nestorian heresy did not only amount to "essentially a roundabout way to talk about the hypostatic union and the relationship of Christ's two natures to his person," but rather, as the Council in question itself stated, divided Jesus Christ into two persons, not only two natures (God; man) united in the one divine Person. This is an inescapable conclusion of the misplaced concern about calling Mary 'Mother of God.'
When Elizabeth said that Mary was mother of her "Lord," (Lk 1:43) regardless of whether she understood lord or Lord, only persons are lords. Therefore, since the Word was made flesh, since the Word is this Lord, she is the mother of God. Unless we deny that "the Word was God."
It's that simple.
As Constantinople II said,
The holy synod of Ephesus… has pronounced sentence against the heresy of Nestorius… and all those who might later ... adopt the same opinions as he held ... They express these falsehoods against the true dogmas of the Church, offering worship to two Sons, trying to divide that which cannot be divided, and introducing to both heaven and earth the offense of worship of man. But the sacred band of heavenly spirits worship along with us only one Lord Jesus Christ.
—Second Council of Constantinople, Sentence against the Three Chapters of Nestorius, A.D. 553, sect. 9
The first two canons of Ephesus I, I think, capture the essence of the Nestorian heresy quite well, because their truth, in contradistinction to the heresy of Nestorius, is so obvious and incontravertable (emphasis mine):
Canon I. If anyone does not confess that God is truly Immanuel, and that consequently the Holy Virgin is the Mother of God (inasmuch as according to the flesh she bore the Word of God made flesh), let him be anathema.
Canon II. If anyone does not confess that the Word of God the Father is united, by bond of [His] Person, to flesh—so that Christ, being one with his own flesh, is thus at once both God and man—let him be anathema.
It's crystal clear:
- "The Word [is] God" (Jn 1:1)
- "The Word was made flesh" (Jn 1:14) in Mary (Gal 4:4; Lk 1:35)
- Therefore Mary, mother of the Word who is God, is the mother of God (Lk 1:43)
Mothers give birth to persons, not 'whats.' Else we claim that 'sons' are things and not people—who would dare to say this of God's Son (Gal 4:4)?
Implications of the Orthodox Position
This means that the one Person, the Word, or Son, or Jesus Christ—the same Person with two natures—can be said to have proper to Him both that which is proper to men and that which is proper to God.
In other words, what is said of Christ can be said of either His divine or human nature, but always as belonging directly to the same, one, divine Person (to whom these two natures belong).
Thus Scripture can say (1 Cor 2:8) of those who crucified Jesus, that if they knew of the secret of God's plan:
..they would not have crucified the Lord of Glory
Or more strikingly, Jesus Himself can say (Rev 1:17-18):
Do not fear. I am the First and the Last, and the Living One: and I was before dead, and behold: I live forever ...
Or again, if Jesus, Mary's Son, were not at all times God, it would be false for Him to claim something like:
John 8:58 Jesus said to them, Amen, Amen I say to you: before Abraham was born, I am.
John 17:5 And now Father, glorify me, with yourself, with that glory I had with you before the world was.
And of course everyone is aware that Jesus thirsted and ate, whereas in His divine nature, He has no need of such: His human nature, which is real and not fake, did.
People can claim the Father or the Holy Spirit died on the cross when they become incarnate like the Word did!
Until then, the Word is God and He became flesh and died for us. Not the Father. Not the Holy Spirit.
It's worrying, theologically, if one thinks that each Person of the Trinity is not fully God without being the other Persons, as was suggested. The Trinity isn't a group of Gods. It is the one God. Such is to deny the Trinity. The Word became flesh, not the Father, or the Spirit, yet the Word wasn't 'not God because He isn't the Trinity.' He was "God." And thus the mother He chose is the Mother of God whether it's comfortable or not.