The purpose of this thread is to compare to fifth century Christological statements. The first is the Definition of Chalcedon (451 A.D., no, the word "Chalcedon" is not being defined):
"Following, then, the holy fathers, we unite in teaching all men to confess the one and only Son, our Lord Jesus Christ. This selfsame one is perfect both in deity and in humanness; this selfsame one is also actually God and actually man, with a rational* soul and a body. He is of the same reality^ as God as far as his deity is concerned and of the same reality as we ourselves as far as his humanness is concerned; thus like us in all respects, sin only excepted. Before time began he was begotten of the Father, in respect of his deity, and now in these "last days," for us and behalf of our salvation, this selfsame one was born of Mary the virgin, who is God-bearer in respect of his humanness.
We also teach that we apprehend this one and only Christ-Son, Lord, only-begotten -- in two natures; and we do this without confusing the two natures, without transmuting one nature into the other, without dividing them into two separate categories, without contrasting them according to area or function. The distinctiveness of each nature is not nullified by the union. Instead, the "properties" of each nature are conserved and both natures concur in one "person" and in one reality. They are not divided or cut into two persons, but are together the one and only and only-begotten Word# of God, the Lord Jesus Christ. Thus have the prophets of old testified; thus the Lord Jesus Christ himself taught us; thus the Symbol of Fathers+ has handed down to us."
*human
^hypostasis
#logos
+referring to the Nicene Creed of 325 A.D. as amended at Constantinople in 381 A.D.
The second is the Synod of Mar Aqaq of 486 A.D., which opposed the Definition of Chalcedon.
"But our faith in the dispensation of Christ should also be in a confession of two natures of Godhead and manhood, none of us venturing to introduce mixture, commingling, or confusion into the distinctions of those two natures. Instead, while Godhead remains and is preserved in that which belongs to it, and manhood in that which belongs to it, we combine the copies of their natures in one Lordship and one worship because of the perfect and inseparable conjunction which the Godhead had with the manhood. If anyone thinks or teaches others that suffering and change adhere to the Godhead of our Lord, not preserving - in regard to the union of the parsopa of our Savior - the confession of perfect God and perfect man, the same shall be anathema."
In part because of the Definition of Chalcedon, many trinitarians (and even oneness folks) talk about Jesus' divinity and His humanity as if they're interchangeable. Thus, it wasn't the man Christ Jesus that died on the cross but God that died on the cross. It wasn't the man Christ Jesus that rose from the dead but God that rose from the dead. Thus also, Mary becomes not the mother of Christ but the mother of God. Also, it should be kept in mind that "person" may not be an accurate translation of the word used in the Definition of Chalcedon, particularly since the Latin word used was "persona," which has an identical English equivalent.
It seems to me, as it may have to Nestorius in the fifth century, that commingling Jesus' divinity and his humanity denies the very nature of divinity as being something eternal, something incapable of dying, incapable of suffering (in the sense of physical pain, hunger, etc.). To quote Nestorius' second letter to Cyril, "I also applaud your statement that God the Word needed no second generation from a woman, and your confession that the godhead is incapable of suffering. Such statements are truly orthodox and equally opposed to the evil opinions of all heretics about the Lord's natures. If the remainder was an attempt to introduce some hidden and incomprehensible wisdom to the ears of the readers, it is for your sharpness to decide. In my view these subsequent views seemed to subvert what came first. They suggested that he who had at the beginning been proclaimed as impassible and incapable of a second generation had somehow become capable of suffering and freshly created, as though what belonged to God the Word by nature had been destroyed by his conjunction with his temple or as though people considered it not enough that the sinless temple, which is inseparable from the divine nature, should have endured birth and death for sinners, or finally as though the Lord's voice was not deserving of credence when it cried out to the Jews: 'Destroy this temple and in three days I will raise it up.'' He did not say, 'Destroy my godhead and in three days it will be raised up.'"
While the Definition of Chalcedon was directed at the Monophysites (who believed Christ had only one nature; the Synod at Mar Aqaq was not a monophysite synod but one that supported Nestorius), elements of it addressed things that were brought up 20 years earlier at Ephesus when Cyril was opposing Nestorius (in a Council that Nestorius requested).
Nestorius provided evidence from scripture in his challenging Cyril:
Holy scripture, wherever it recalls the Lord's economy, speaks of the birth and suffering not of the godhead but of the humanity of Christ, so that the holy virgin is more accurately termed mother of Christ than mother of God. Hear these words that the gospels proclaim: "The book of the generation of Jesus Christ, son of David, son of Abraham." It is clear that God the Word was not the son of David...Again, scripture says when speaking of his passion: "God sending his own Son in the likeness of sinful flesh and for sin, he condemned sin in the flesh"; and again "Christ died for our sins" and "Christ having suffered in the flesh"; and "This is", not "my godhead", but "my body, broken for you".
In the end, Cyril came up with 12 anathemas against Cyril that were accepted by the Council (a council that Nestorius didn't attend at least in part because Cyril convened it before giving bishops from the east time to arrive). I think some of these anathemas are actually straw men, arguing against things Nestorius never said. You can read the anathemas here:
http://www.ewtn.com/library/COUNCILS/EPHESUS.HTM#5
To commingle or not to commingle: that is the question. Whether it is wise to attribute to divinity those things which pertain the Christ's humanity and to attribute to humanity those things which pertain the Christ's divinity - on the sole basis that divinity and humanity are combined in one Lord Jesus Christ - I open it up for discussion.