Eran. -This is indisputable.
Orth. -Since then we assert that some terms are common to the Holy Trinity, and some peculiar to each hypostasis, do we assert the term "immutable" to be common to the substance or peculiar to any hypostasis?
Eran. -The term "immutable" is common to the Trinity, for it is impossible for part of the substance to be mutable and part immutable.
Orth. -You have well said, for as the term mortal is common to mankind, so are "immutable" and "invariable" to the Holy Trinity. So the only-begotten Son is immutable, as are both the Father that begat Him and the Holy Ghost.
Eran. -Immutable.
Orth. -How then do you advance the statement in the gospel "the word became flesh." and predicate mutation of the immutable nature?
Eran. -We assert Him to have been made flesh not by mutation, but as He Him self knows.
Orth. -If He is not said to have become flesh by taking flesh, one of two things must be asserted, either that he underwent the mutation into flesh, or was only so seen in appearance, and in reality was God without flesh.
Eran. -This is the doctrine of the disciples of Valentinus, Marcion, and of the Manichees, but we have been taught without dispute that the divine Word was made flesh.
Orth. -But in what sense do you mean "was made flesh"? "Took flesh," or "was changed into flesh"?
Eran. -As we have heard the evangelist say, "the word was made flesh."
Orth. -In what sense do you understand "was made"?
Eran. -He who underwent mutation into flesh was made flesh, and, as I said just now, as He knows. But we know that with Him all things are possible, for He changed the water of the Nile into blood, and day into night, and made the sea dry land, and filled the dry wilderness with water, and we hear the prophet saying "Whatsoever the Lord pleased that did He in heaven, and in earth, in the seas and all deep places."
Orth. -The creature is transformed by the Creator as He will, for it is mutable and obeys the nod of Him that fashioned it. But His nature is immutable and invariable, wherefore of the creature the prophet saith "He that maketh and transformeth all things." But of the divine Word the great David says "Thou art the same and thy years shall not fail." And again the same God says of Himself "For I am the Lord and I change not."
Eran. -What is hidden ought not to "be enquired into."
Orth. -Nor yet what is plain to be altogether ignored.
Eran. -I am not aware of the manner of the incarnation. I have heard that the Word was made flesh.
Orth. -If He was made flesh by mutation He did not remain what He was before, and this is easily intelligible from several analogies. Sand, for instance, when it is subjected to heat, first becomes fluid, then is changed and congealed into glass, and at the time of the change alters its name, for it is no longer called sand but glass.
Eran. -So it is.
Orth. -And while we call the fruit of the vine grape, when once we have pressed it, we speak of it no longer as grape, but as wine.
Eran. -Certainly.
Orth. -And the wine itself, after it has undergone a change, it is our custom to name no longer wine, but vinegar.
Eran. -True.
Orth. -And similarly stone when burnt and in solution is no longer called stone, but lime. And innumerable other similar instances might be found where mutation involves a change of name.
Eran. -Agreed.