The problem with “proving” the uncreated divinity of our Lord is that it has never actually been authentically in question amongst those who adhere to Apostolic doctrine for nearly two millennia. There are many direct and explicit references to such by Koine Greek word meanings, and the many Hebraicisms that came before that.
There has never been valid opposition to the Son’s uncreated divinity. The Arian conflict surrounding the need for the Council of Nicea set the stage for dismissing even the notion that the Son was created divinity of a different and lesser “kind”.
For a time as much as anyone else, I opposed the Trinity doctrine; but for very explicit reasons inverse to Arians and Unitarians. My contention for a number of years was (and still is, but in a manner befitting adherence to Orthodox Trinitarian dogma) that modern perceptions were ignorantly Tritheistic, mistakenly conceptualizing three individuated beings.
But to have to argue ad infinitum with Unitarians is beyond absurd, and is always proven futile; for Unitarians never come to these forums to learn or ask about what seems to them impossible, or at least implausible. They come here with a view rooted in Cognitive Dissonance and Confirmation Bias, and an understanding devoid of true linguistic knowledge of form and meaning as grammar and semantics with lexical explication.
So to engage with Unitarians is somewhat akin to engaging in an argument with one’s own children. It’s not a matter of convincing them of any particular truth of a certain doctrine, but it’s a fruitless engagement in a power struggle when there is no power struggle. The Trinity doctrine is rightly default Christian doctrine, and for reasons far beyond the faulty ideology of Unitarianism.
To engage Unitarians in well-intentioned debate is to engage in a power struggle with a child defying authority. There is a great sense of loss just by entertaining the overt inappropriate challenge to historical and lexical authority.
My own excurses should be an example of many. Unitarians ignore the basics of Greek grammar and lexicography to falsely interpret and apply any and all usage of scripture. They selectively ignore the carefully distributed and irrefutable references to the divinity of our Lord based upon linguistic absolutes of language form and meaning.
There are many verses with words that have definitions wherein the divinity of our Lord is undeniable. And that aggregate assemblage of terms is the systematic by which the Trinity doctrine is presented. The question is not one of the Lord’s divinity being absolute fact in the inspired text; the question has always historically been how to maintain Monotheism in light of there being a clear “threenees” to the singular Divinity that is Father, Son, and Holy Spirit.
The question has always primarily been about eliminating what is not rather than asserting what is. So there was an extended process of having to eliminate things that were being innappropriately included, which is why Ecumenical Councils were convened. NOT initially to establish what Christian doctrine IS (though that always emerged), but to clearly eliminate and anathematize what IS NOT Christian doctrine.
The divinity of our Lord was clearly established long before Nicea; it was just a matter of explicating that to/for/among all Believers while maintaining Monotheism. The first real quarrel was NOT whether Christ was divine or not, but whether the Son was a lower and/or lesser form of divinity who had a seeming beginning. Any Unitarian considerations were long dismissed as the Judaizing fallacy and heresy that a human-only Messiah is as an antichrist concept. The arguments were ALL about what “kind” of divinity the Son represented relative to the Father, and the same consideration for the Holy Spirit.
Created divinity (Arianism) was eliminated for ultimately the same reasons as Unitarianism was eliminated. Sabellianism and other forms of Modalism were eliminated as well, as were a number of other upstart considerations attempting to gain traction in the early apologetic period and going forward until these issues had all been addressed for several centuries.
Nicea, Constantinople, and Chalcedon all settled the primary exclusions of Theology Proper for Paterology, Christology, and Pneumatology. Though there can still be theological pursuit in understanding these areas and possibly expressing them in appropriate modern terms, there is no room to challenge or change the results of the Apostolic pursuits of the Early Fathers in determining the details of our Lord’s divinity. No stone was theologically left unturned to demonstrate clearly what Apostolic doctrine IS according to the inspired text.
When John 1:1 utlilizes anarthrous Theos for the Word in contrast to articular Theos for the Father respectively, it is clear the Son is divinity.
When the first few verses of Hebrews state that the Son is the express image (charakter) of God’s person (hypostasis), this is an unequivocal proof that the Son is divine based simply upon the lexical meaning and application of those terms.
When Philippians refers to the Son being in the form (morphe) of God and coming in the form (schema) of a servant, these are absolutely and unquestionably clear proofs of the Son’s divinity.
There are others in tandem to these, but any ONE of these would suffice and all of these and others most certainly do, regardly of how that divinity is then addressed to maintain Monotheism.
The singular ousia is the singular “what-ness” that is divinity. No criticism of Polytheism can be leveled when the divinity is not plural. And all other questions have been answered for a very long time by early theologians that have no modern equivalent, whatever our resources and prowess.
Humanity-only (Unitarianism), Humanity-become-divinity - in whatever manner at whatever time in whatever way to whatever degree as ontology or economy (Adooptionism), Created Divinity, Modalistic Divinity - again in several forms, and many other considerations were excluded; as were many Christological considerations regarding “how” Christ was both divine and humanity.
These were all exhautively addressed centuries ago by those who were far more linguistically and theologically adept than we are today. And the fact remains that the Trinitarian formulaic explanation and explication of terms for Father, Son, and Holy Spirit being eternal and uncreated SINGULAR divinity has been established as the irretuable standard of the Christian faith.
I myself still have a handful of concerns about how modern western English speakers understand and express the Trinity doctrine; and I’ve spent two decades attmempting to explicate that and provide clarity. That unfortuately included a foray into anti-Trinitarian challenge; but it was a challenge that most modern Trinitarians aren’t actually fully Trinitarian, NOT that the Trinity doctrine itself was in error.
My assertions remain my concern, but pale in comparison to any and all who would challenge the eternal and uncreated singular divinity of our Lord, the Father, and the Holy Spirit.
Unitarians are at the bottom of the list, for there is no legitimate challenge to the divinity of our Lord that can be made. Regardless of “how” He was divine, and what “kind” of divinity He had/has; there can be NO valid challenge to the divinity of Jesus Christ, the eternal and uncreated Son of the one true and living God.
And in addition to that, the “hows”, “whys”, and “kind” considerations of our Lord’s divinity have all been extensively and exhaustively examined and considered to present the assemblage of lexical terms that comprise the Trinity doctrine and all the facets of Christian Paterology, Christology, and Pneumatology.
The Trinity doctrine is not an issue that is up for valid debate, particularly with those who are both linguistically and historically ignorant and represent both modern innovation and historical revisionism along with invalid doctrinal revisionism.
Unitarians (and others) are antichrist. Period. Full stop.