Orthodox: We did not only ask where is the place that you say the human nature is, but also if it is counted and is in the Trinity and with the Trinity or not. For you said that [the humanity] is not believed to exist in the Trinity as a hypostasis is in a nature because the humanity is not as one of the hypostases which are in the nature of the Trinity, which are of the same nature. For what is not reckoned as a [hypostasis] by number and by convention (although it is not of the same nature) has no existence, even if it is numbered along side of one of the [hypostases]. But if [the humanity] is numbered along side all of them, as it is numbered along side of one, [then] it is established clearly that you confess a quaternity.
Nestorian: Let no one slanderously ascribe a quaternity to us, because it is foreign in word and thought to our doctrine. For how is [your accusation that we teach a quaternity] confirmed concerning us, when we confess three hypostases established and existing in one Divine nature? And the [human] hypostasis, which we say is other than the [three] and their nature, we do not place in [their] number. For the human hypostasis is known and counted in the place where it exists. But this is in one of the Trinity, and not in the whole of the Trinity, or along with it. But if not, then also the human nature, which is acknowledged by you, is established in the whole of the Trinity, and it is numbered with the general nature of Divinity.
Doctrine of a human hypostasis
Orthodox: You run and flee to this human nature which we affirm, without explaining a reason for accepting your [doctrine of a human hypostasis] which you care for. For the fact that [not numbering the human nature in one of the Trinity] would [lead to] the whole Trinity generally possessing the human nature, does not need to be proven by either our arguments or yours. But this last thing which you say, that the [human nature] is not numbered with the Divine nature, this is well known, because [the human nature] receives the number of its natural knowability from its belonging to the hypostasis of the Son. Thus, whether it is reckoned along side of the hypostases of the Father and the Spirit or along side the common nature of the Trinity, it receives the number of its knowability [from the Son]. But if there is also a [human] hypostasis as you affirm, then in the same way that its nature is [united] with the nature of Divinity [in Christ], so its hypostasis [would] also be counted with the three hypostases which are in [the Trinity].
Nestorian: Is the God Word born from the Virgin naturally or by grace?
Orthodox: Naturally when as a man, but by grace and by the economy of union as God. But tell me yourself whether a hypostasis is born which is not confessed to be the Son?
Nestorian: It is known that every hypostasis which is born is confessed to be the son of that from which it is born.
Orthodox: Therefore when you confess two hypostases, and it is clear that you say that there are [separate] births for them, one from the Father and another from Mary, you are confessing two sons.
Nestorian: We confess and are zealous for one sonship and person in these two hypostases.
Orthodox: Then tell me do you say that this one sonship which you confess is natural to both hypostases or to one alone? If it is the former, behold two sons and two Christs equal in nature. But if it is the second, there remains one of the hypostases which is not called son or begotten.
And again it is asked: Is a hypostasis born without sonship? and if there is sonship to every hypostasis. Clearly because of this there are two sons.
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