The Bible’s affirmation that Christ is both God and man yet one Christ is the mystery upon which all of redemption hangs. The Confession does not attempt to explain this mystery but presents us the classic Chalcedonian paradox, saying, “two whole, perfect, and distinct natures were inseparably joined together in one person, without conversion, composition, or confusion; which person is very God and very man, yet one Christ, the only mediator between God and man” (2LBCF 8.2). This language, while having much precision and philosophical depth, nevertheless is remarkable in its employment of that precision and depth to guard the simple mystery of Scripture against the pollution of any extra-biblical explanation which may compromise the absoluteness of those propositions: very God, very man, but one Christ. As Berkhof would say, “[The formula of Chalcedon] merely sought to guard the truth against the errors of the theorizers, and to give a formulation of it which would ward off various, palpably unscriptural, constructions of the truth.” It does not say how Christ is one person or how the uniting of the natures into one person avoids conversion, composition, and confusion; it merely states that all this takes place without anything proper to the natures either being lost or mixed with elements foreign to them – that is, anything true about the natures of God and man remain true throughout the incarnation, and anything necessary for Christ to remain one person (the same eternally existing “Son of God, the second person in the Holy Trinity” [8.2]) is likewise true.
Since the terms “nature” and “person” are commonplace in ordinary speech and are often used instinctively, it is easy to take their meanings for granted and unconsciously import concepts into those words that are neither derived from special revelation nor historically understood to be necessarily contained in the words themselves. Thus, if we are indeed using these technical terms to identify our views with those who crafted them (as the writers of our Confession intended to do), then it behooves us to understand what was originally meant by them and how they have been understood throughout Church history. Otherwise, we may risk coming up with an understanding of these doctrines that has continuity with what the framers meant in word only, at which point we ought to either conform our concepts to theirs or else – for the sake of transparency – employ different terminology to make our departures from them clear. It is the author’s conviction that no departures are needed.
Chalcedonian Christology before Chalcedon
The terminology of Chalcedon was refined over time, but the substance of the doctrines can be found as early as extant writings on the topic exist. This is because it is a manifestly biblical doctrine, as can be seen by the many places attributing uniquely human characteristics to Him, such as hunger (Matt. 4:2), thirst (Jn. 19:28), ignorance (Matt. 24:36), growth (Lk. 2:52), passibility (Jn. 12:27), as well as the uniquely divine characteristics of being beyond necessity (Jn. 4:32), possessing omniscience (Jn. 16:30), eternality (Jn. 8:58), omnipresence (Jn. 3:13 in the Majority Text and Textus Receptus, also Matt. 18:20), and omnipotence (Matt. 14:19, Jn. 2:9, etc.). Besides all these traits being attributed to the same Jesus, the unity of His person is proved by those texts which predicate divine attributes of a name derived from His human nature and vice versa (Jn. 3:13 and Acts 20:28). All the human attributes can be said to be the attributes of the Son of God and all the divine attributes can be said to be the attributes of the Son of Man, they being one and the same God-man, the Lord Jesus Christ.
Given the clear biblical basis and its central importance to the faith once delivered unto the saints, it is unsurprising to see many references to these truths centuries before the Council of Chalcedon, especially because three early heresies the Church combatted – Docetism, Ebionism, and Gnosticism – each denied at least one of the truths dogmatically upheld by Chalcedon; Docetism denied the authenticity of Christ’s human nature, Ebionism denied the fullness of Christ’s divine nature, and Gnosticism divides the unity of Christ’s person by ascribing His various titles to distinct, individual Aeons. As such, there was a pressing need to emphasize the genuineness of Christ’s two natures and the unity of all His titles and attributes in His one person in the pre-Chalcedonian fathers.
In the early 2nd Century, for example, we find the epistles of Ignatius (d. 108/140) repeatedly returning to the theme of the reality of the incarnation as he fights against the Docetic heresy. In them, he maintains that Christ is both fully God and fully man, having what is proper to both natures without dividing His person, saying, “There is one Physician who is possessed both of flesh and spirit; both made and not made; God existing in flesh; true life in death; both of Mary and of God; first passible and then impassible – even Jesus Christ our Lord.” Ignatius gives us a series of contrasts as being simultaneously true of Christ, who is but “one Physician.” Christ is uniquely possessed of both “flesh and spirit,” which is to say a human and a divine nature (cf. Jn. 4:24 for this use of spirit), the latter of which remains unaltered in the incarnation as being “impassible.” It is also clear in Ignatius that he follows the biblical pattern of referring to more than just the physical body when he says “flesh,” which to him encompasses even the human will. He shows this, for instance, when he clarifies that Christ’s subjection to the Father is only “according to the flesh,” implying (since the context is volitional subjection) that Christ has a human will which can subject itself apart from any Spirit-nature submission. There is every reason to infer from Ignatius’ writings that he conceives of the complete human and divine natures existing in the one person of Christ, with neither nature losing any of its proper dignity.
In the beginning of the 3rd Century, Tertullian’s (155-220) description of the incarnation is remarkably vivid. Writing against the Sabellian conception that the Father and Son are one person respectively manifested as Spirit and flesh, Tertullian expressly affirms that it was the eternal Son (not the Father) who became flesh without any “transfiguration,” but rather “by a real clothing of Himself in flesh.” He rejects any idea of the Word’s nature changing both because “we must needs believe God to be unchangeable” and because such an incarnation would result in a being that is neither human nor divine, when Christ is both:
If the Word became flesh by a transfiguration and change of substance, it follows at once that Jesus must be a substance compounded of two substances – of flesh and spirit… the one being changed by the other, and a third substance produced. Jesus, therefore, cannot at this rate be God for He has ceased to be the Word, which was made flesh; nor can He be Man incarnate for He is not properly flesh, and it was flesh which the Word became. Being compounded, therefore, of both, He actually is neither; He is rather some third substance, very different from either. But the truth is, we find that He is expressly set forth as both God and Man… differing no doubt according to each substance in its own especial property, inasmuch as the Word is nothing else but God, and the flesh nothing else but Man… We see plainly the twofold state, which is not confounded, but conjoined in One Person – Jesus, God and Man… the property of each nature is so wholly preserved, that the Spirit on the one hand did all things in Jesus suitable to Itself, such as miracles, and mighty deeds, and wonders; and the Flesh, on the other hand, exhibited the affections which belong to it.Tertullian, Against Praxeas, XXVII
In this very clear passage, Tertullian affirms all the mysteries of Chalcedon, upholding the divine and human natures without either mixture or any separation into multiple persons, but rather united in the one God-man, Jesus Christ. He explicitly uses the language of personhood and nature to describe the unity and distinctions in Christ, respectively, and also shows his willingness to engage in partitive exegesis. Thus, we have not only the doctrine, but the very language of Chalcedon presenting itself in barely more than a century after the close of the New Testament canon.
Nor is such pre-Chalcedon clarity unique to Tertullian. Origen (185-253), despite all his other issues, speaks thusly of Christ:
We see in him some things so human that they appear in no way to differ from the common frailty of mortals, and some things so divine that they are appropriate to nothing else but the primal and ineffable nature of deity… For this reason we must pursue our contemplation with all fear and reverence, as we seek to prove how the reality of each nature exists in one and the same person, in such a way that nothing unworthy or unfitting may be thought to reside in that divine and ineffable existence, nor on the other hand may the events of his life be supposed to be the illusions caused by deceptive fantasies.Origen, On First Principles, II.6.2
We see again the language of one person and two natures – in fact, two natures “in one and the same person.” This language is at odds with the later Monophysite heretics who affirmed only that Christ was of two natures but refused to acquiesce to Christ existing in two natures. He also goes on to contradict the later Apollinarian heresy, saying, “there did exist in Christ a human and rational soul.” It is a great demonstration of the antiquity of a doctrine when both the language of its definitive expression as well as language that would exclude the heresies it meant to combat appears long before that definitive expression was formalized.
The unity of the full, uncorrupted natures in one person is also exhibited vividly in Athanasius’ (296/8-373) work, On the Incarnation of our Lord Jesus Christ, Against Apollinaris, in the fourth century, but because both the doctrine and language can be found in the previously quoted writers, it will be sufficient to commend it for those interested in further study and proceed to the history of the Council of Chalcedon.
The Council of Chalcedon
Despite orthodox Christological teaching being found in every generation of the Church, there were some within the growing ecclesiastical hierarchies that departed from the simplicity of the mystery that required a response. The two immediate targets of the creed were the Nestorians and the Eutychians or Monophysites, who despite having opposite conclusions possessed the same core conviction: personhood and nature are inseparably linked. Therefore, either Christ has two natures and is two persons (Nestorianism) or else He is one person with one nature (Eutychianism). In other words, the two heresies relied on pre-conceived, extra-biblical notions of personhood and nature to supplant the biblical truth already deeply rooted in Church tradition. The Council of Chalcedon (451), on the other hand, took the approach of merely stating biblical truth to the exclusion of the heresies without attempting to explain the mystery. In so doing, it began the process of permanently modifying the limits of the previously ambiguous terminology in subjection to orthodoxy, rather than letting the terminology modify orthodoxy like the heretics did.
The semantic ranges of the terms “nature” and “person” had to be subjugated because the equivalents used in the East did not perfectly overlap with those of the West. This is partly because the Greek words for person and nature may have had some semantic overlap in themselves. When it comes to nature, there was also the concern that speaking of two natures may imply a separability of the natures. This was the concern of Cyril of Alexandria (376-444), a champion of orthodoxy in the East, who despite affirming the substance of the doctrine of two natures and even subscribing to that language in the Formula of Union in 433, nevertheless preferred to speak of “one incarnate nature,” because things that thoroughly unite two sub-natures are still usually considered to be one nature and only two theoretically – e.g., there is said to be one nature of man despite a man being formed from two sub-natures, a body and a soul, which remain distinct and complete. To this day, there are those who follow Cyril of Alexandria on this point known as “Miaphysites,” who are generally acknowledged to disagree only in terminology rather than the substance of Chalcedon, as their recent dialogues with Roman Catholics and the Eastern Orthodox have shown. Nevertheless, the overwhelming majority of professing Christians have adopted the terminology of Chalcedon as a safeguard against both the errors of Nestorianism and Monophysitism. Further, later theologians such as John of Damascus (675/6-749) have argued that even though we use the language of “one human nature” for beings with perfect and distinct souls and bodies, the language of “one Christ nature” is nevertheless inappropriate, because “there is no predicable form of Christlihood” like there is with humanity – i.e., the union between divinity and humanity in the person of Christ is unique and not a universal nature that could be predicated of other individuals like the composite nature of humanity. Preserving the language of “one person in two natures” helps to preserve the uniqueness of the incarnation, and the conception of nature was refined to allow for this important distinction.
Turning to the question of “person,” it is, as Boethius (477-524) says, “a matter of very great perplexity.” This is, in large part, because the Latin term for person (persona) has two counterparts in the Greek – namely, πρόσωπον (prosopon) and ὑπόστασις (hypostasis) – and both of them can lead to grave misconceptions when applied to the persons of the Trinity. On the one hand, πρόσωπον, like the probable origin of persona, has an association with theatrical masks and usually means “face” when used in Scripture, whereas ὑπόστασις (which, according to Boethius and later Christian tradition, is the more fitting counterpart of “persona”) is etymologically identical to the Latin “substantia” (our “substance”) and literally means “put under.” Therefore, to use πρόσωπον for the persons of the Trinity risks conveying modalism by treating the persons as masks or mere roles, whereas using ὑπόστασις risked conveying tritheism by dividing the substance of God. Before the subsequent standardization of terminology, ὑπόστασις indeed retained the connotation of “substance” in many of its usages, and in fact seems to be treated as interchangeable with οὐσία (ousia) in the anathemas of Nicaea. Nevertheless, ὑπόστασις had the additional connotation of some concrete thing of a higher value, and accordingly was not used of irrational animals but only of such things as men, angels, or God. As such, the term began to lose much of its original attachment to οὐσία, being defined according to Boethius’ textbook definition of persona: “the individual substance of a rational nature” – which is to say, a rational subsistence which acquires “substance through the medium of particulars.” It is a rational, concrete thing which has its nature by virtue of being an instance of that nature, which in the case of the persons of the Trinity would be nothing else besides that nature subsisting in their peculiar relative properties by which they receive that nature and are that nature. This was what was meant by “person” in its Chalcedonian and post-Chalcedonian expressions.
The Aftermath of Chalcedon
Despite some dissenting groups in the East, professing Christians at large came to embrace both the language and doctrines of Chalcedon. Controversies, however, immediately followed suit, largely because of concerns over certain bishops (Theodoret of Cyrus [393-458/66] and Ibas of Edessa [d. 457]) that were reinstated at Chalcedon, the feared impact of their writings, and also because of civil and ecclesiastical controversies between Pope Vigilius (497-555) and Emperor Justinian the Great (482-565). Concerning the doctrinal element, there were fears in the East that the writings of Theoredet and Ibas (as well as Theodore of Mopsuestia [350-428]) would allow for a form of crypto-Nestorianism to seep into the teachings of the Church, because it was believed that they taught that Christ was not the person of the Logos in the flesh, but rather that the one person in two natures was a fusion of the human person and divine person together – in other words, the natures remained but Christ was a brand new person rather than the pre-existing second person of the Trinity. Under this view, one could technically affirm the statements of Chalcedon while affirming a quasi-Nestorian distinction between the person of Christ and the person of the Logos, which is why the Second Council of Constantinople (553) became necessary. This council upheld the teachings of Chalcedon that Christ was one person in two natures while providing the further clarification that the person of Jesus Christ is none other than the second person of the Trinity, stating, “There has been no addition of person or subsistence to the holy Trinity even after one of its members, God the Word, becoming human flesh.” Because Justinian refused to grant Pope Vigilius’ request to hold the council in a location that would have allowed more Western bishops to attend (and likely also because of the growing tension between the East and West), the council was predominately composed of Eastern representatives. Nevertheless, it is rightly considered to be ecumenical insofar as Pope Vigilius later approved it and even composed his own Constitution, signed by other Western bishops, which condemned the same errors denounced in Second Constantinople. Today, it is numbered as the fifth of the seven ecumenical councils affirmed by Catholics, the Eastern Orthodox, and some branches of Protestantism. The Reformed, however, generally take exception to its affirmation of the perpetual virginity of Mary and so do not fully subscribe to it like we do to the previous four councils, despite it otherwise being in line with the Christology of our confessions (cf. 8.2 of the 2LBCF).
After that council, the attempt to undermine the full divinity and humanity of the Son arose once more before it was dogmatically laid to rest for nearly a thousand years. It began with an attempt to form a compromise between the Chalcedonians and the remaining Monophysites of the East by affirming a single “energy” (or activity, operation, etc.) in Christ by the Emperor Heraclius (575-641), which was opposed vigorously by Sophronius of Jerusalem (560-638). In the midst of this, Emperor Heraclius recruited Pope Honorius I (d. 638) to assist him, but the Pope simply rejected the whole discussion and instead asserted another heresy – namely, that Christ had one will (monotheletism). Maximus the Confessor (580-662) courageously opposed this distortion, and within a century that Pope would be condemned as an instrument of the Devil in the Third Council of Constantinople (680-681), which forcefully opposed both monotheletism and the single-energy doctrine of Emperor Heraclius and would be reckoned as the sixth ecumenical council. It established firmly what could already be gathered from the writings of previous Church writers – namely, that energy and will are predicates of nature and not person, which can be seen in the very human actions and desires of Christ in His incarnation. Rather than being a single person by virtue of having a single will and energy, the council affirmed that Christ’s one person is established by the pure harmony and subjection of His human will and energy to His divine will and energy, much like the exertion of a human body is subject to the exertion of the human soul in one person. The council quotes the writings of Athanasius, Pope Leo, Cyril of Jerusalem, and others to demonstrate the antiquity of their doctrine, and indeed we have already seen a nascent understanding of this as early as the already quoted Ignatius of Antioch (d. 108/140).
Orthodoxy Established – The Middle Ages through the Reformation
After the sixth council, the history of Christology for nearly the next thousand years is a history of reiteration and confirmation, following the now well-established distinction between nature and person. John of Damascus (675/6-749) brilliantly summarizes all the settled points of Christology in his An Exact Exposition of the Orthodox Faith, affirming the entirety of His en-hypostatic humanity and His Deity – including their respective wills and energies – as existing in the truly one person of the eternal Logos. Thomas Aquinas (1225-1274) explicitly follows Boethius’ definition of person (“an individual substance of a rational nature”) while making it clear how it is to be understood as applying analogously to God, insofar as He is not individualized by matter, His substance is His self-subsistence, and His rational nature is not discursive like ours but rather an intelligent nature “in a general sense.” He also explains how the humanity of Christ does not constitute an additional person because the definition above implies that a person has an independent existence as an individual substance, whereas the humanity of Christ has no such independent existence but has the entirety of its subsistence in the Word. In all of this, neither John of Damascus, Thomas Aquinas, nor the other prominent Medieval thinkers depart or expand upon the definitions of the council, but only summarize, explain, and defend the rationality of the accepted Christological propositions.
At the Reformation, much of the doctrinal and practical accretion of the late Patristic and Middle Ages was overthrown and a return to the purity of the primitive Church was inaugurated. The doctrines of God and Christ as the God-man, however, were at their core left untouched by the great theologians of the 16th and 17th Centuries because they understood them to be faithful to the Scriptures and in fundamental accord with the teachings of the Church from her earliest days. Calvin, for example, uses the classic analogy of the existence of the soul and body in one person to illustrate the complete divinity and humanity existing in the one person of Christ and praises Chalcedon and its condemnation of both Eutychianism and Nestorianism. All the major confessions of the Reformation – including the Augsburg Confession, the Belgic Confession, the Westminster, the Savoy, and 2LBCF – would also affirm these truths. The unanimity behind the understanding of this doctrine can be seen in the words of William Cunningham as late as the 19th Century:
The general doctrine explicitly taught in Scripture upon this subject is, that the Logos, the eternal Son of God, was incarnate, or assumed human nature, or became man. Of course He could not cease to be God, to be fully possessed of the divine nature, with all divine perfections and prerogatives; and accordingly, all who admit that He was from eternity possessed of the divine nature, and that He became incarnate in time, believe that He continues to be very God, to possess the divine nature entire and unchanged… Having thus taken a true body, formed of the substance of the Virgin, He continued ever after to retain it, as is manifest in the whole history of His life, of His death, and of the period succeeding His resurrection; and He has it still at the right hand of God. He took also a reasonable soul, possessed of all the ordinary faculties and capacities of the souls of other men, including a power of volition, which is asserted in opposition to the error of the Monothelites.William Cunningham, Historical Theology: A Review of the Principal Doctrinal Discussions in the Christian Church since the Apostolic Age, 311-13
In this short section, the teachings of all the Christological councils are summarized: the unity of two natures in the person of the Logos and their perfect continuance – the properties and prerogatives of each being entirely preserved throughout.
A Shift – The Revising of the Divine Nature and Personhood
Long before its impact in theology, a shift in the understanding of personhood was underway in philosophy. John Locke (1632-1704) gave the following definition of personhood:
[It is] a thinking intelligent being, that has reason and reflection, and can consider itself, as itself, the same thinking thing in different times and places; which it does only by that consciousness which is inseparable from thinking…When we hear, smell, taste, feel, meditate, or will any thing, we know that we do so. Thus it is always as to our present sensations and perceptions; and by this every one is to himself that which he calls self.John Locke, An Essay Concerning Human Understanding, 225-6
While John Locke was exclusively concerned with the personhood of man when he said this, it is no surprise that – when the definition of personhood in God ceased to be a controversial issue – the more popular understanding of personhood he established began to even seep into theology proper. This, however, would create innumerable problems when meshed with the classic doctrines of God and the Mediator. Whereas the old definition of personhood focused on objective qualities – a complete, individual substance of a rational (but not necessarily discursive) nature – Locke’s definition focuses on subjective qualities – i.e., the conscious experience while perceiving external sensations and the output of its discursive reflection. Whereas the persons of the Trinity have been classically understood as timeless, simple, and impassible, they would have to become timebound, complex, and passible to become Lockean persons. In other words, they would have to become a lot like us, having qualities classically ascribed to human souls.
Beginning with the 18th century, a few theologians influenced by such concepts of personhood began referring to the Trinity as “three centers of consciousness,” which was a novelty that began chipping away at the foundation of the sixth ecumenical council, whose doctrine was based on energy and will being properties of nature instead of person. The new subjective emphasis of personhood also laid the ground for the kenotic heresy since – under Locke’s framework – continuity of consciousness but not continuity of substance was necessary for a person to remain the same person, and thus many divine attributes and prerogatives could be laid aside without the Logos becoming a different person. Even in more orthodox circles, men such as John Orr (1844-1913) began to claim that the natural complete otherness between God and man was “the radical weakness of the old Christology,” and that man being, as he says, “capax infiniti… furnishes a starting-point for the conceivability of the incarnation,” in direct opposition to the classic Reformation slogan. Orr goes as far as to say the following of the theology of Appollinaris (who conceived of the Logos as merely replacing a human soul):
There is at least one element of truth in his speculations to which the Church of that time was not fitted to do justice… The Logos, he held, does not stand apart from man, as something foreign to his essence, but is rather Himself the archetype of humanity—has the potency of humanity eternally within Himself… There is here a step towards the recognition of that inward kindredness of God to the human spirit—that natural grounding of the soul of man in the Logos as the light and life of man—which must be taken account of in any adequate doctrine of the incarnation.James Orr, The Progress of Dogma: Being the Elliot Lectures, 180-1
What Orr was only sympathetic to, however, has been carried out in its entirety by William Lane Craig, who self-styles his model as “Neo-Apollinarianism.” Whereas old-school Apollinarianism posited that Christ had an incomplete human nature, Neo-Apollinarianism claims the ability to adhere to Chalcedon because the second person of the Trinity already had the fundamental qualities of a human soul – “rationality, self-consciousness, freedom of the will, and so forth. Christ already possessed those in his divine nature.” Therefore, according to Craig’s model, “the soul of the human nature [in Christ] is the person of the second person of the Trinity.” In his model, Craig starts with many of the familiar attributes of Lockean personhood, assumes that the Logos (as a person) must possess them, and therefore imagines that Christ having a human soul in addition to His eternal personhood would result in Nestorianism.
It is often alleged that promoters of the classical doctrines of God and Christology are guilty of subordinating Scripture to philosophy. As we have seen, however, the early Church did not uncritically lift and apply the language of pagan philosophy when articulating the doctrine of Christ, but rather refined and subordinated the language of personhood and nature to accommodate the teachings of Scripture concerning the one who is truly God and truly man. By contrast, much of modern Christology has done the reverse, taking novel secular concepts of personhood not discussed in Scripture and importing that back into the historical terminology. Given that this process appears to have largely unfolded subconsciously, the danger may be that much greater of being spoiled through philosophy (Col. 2:8).
Note: The above paper was originally written by me for a class at CBTS
 Louis Berkhof, The History of Christian Doctrine (West Linn: Monergism Books, 2018), chap. 4, par. 1.https://www.monergism.com/thethreshold/sdg/berkhof/The%20History%20of%20Christian%20Doctri%20-%20Louis%20Berkhof.pdf.
 Ignatius, The Epistle of Ignatius to the Ephesians (Shorter Version), ed. Thomas Horn and trans. Alexander Roberts and James Donaldson, The Researchers Library of Ancient Texts, vol. 2 (Crane: Defense, 2012), VII.
 Ignatius, The Epistle of Ignatius to the Magnesians (Shorter Version), ed. Thomas Horn and trans. Alexander Roberts and James Donaldson, The Researchers Library of Ancient Texts, vol. 2 (Crane: Defense, 2012), XIII.
 Tertullian, Against Praxeas, trans. Dr. O. W. Holmes, Tertullian Collection (Aeterna Press, 2016), XXVII.
 Origen, On First Principles, ed. Tania M. Geist and trans. G. W. Butterworth (Notre Dame: Ave Maria Press, 2013), II.6.2.
 Ibid, II.6.5. Admittedly, Origen had an unorthodox conception of the pre-existence of souls, but he nevertheless understood that – regardless of what a human soul is – Christ had to have a genuine human soul as part of His full humanity
 N. R. Needham, 2000 Years of Christ’s Power,vol. 1, revised ed. (London: Grace Publications Trust, 2002), 269.
 Cyril of Alexanderia, Second Letter of Cyril to Succensus, 3.
 John of Damascus, An Exact Exposition of the Orthodox Faith, ed. Philip Schaff and Henry Wace, A Select Library of the Nicene and Post-Nicene Fathers of the Christian Church, 2nd series, vol. 9, (Edinburgh: T&T Clark, 1898), https://ccel.org/ccel/schaff/npnf209/npnf209.iii.iv.iii.iii.html, III.3.
 Boethius, A Treatise Against Eutyches and Nestorius, ed. Jeffrey Henderson and trans. H. F. Stewart, E. K. Rand, and S. J. Tester, Boethius (Cambridge: Harvard University Press, 1973), II.
 Ibid, III.
 Second Council of Constantinople, ed. Norman P. Tanner, Decrees of the Ecumenical Councils (Washington, D.C: Georgetown University Press, 1990),https://www.papalencyclicals.net/councils/ecum05.htm, Anathema 5.
 Needham, 348
 The Third Council of Constantinople, The Definition of Faith, ed. Philip Schaff A Select Library of the Nicene and Post-Nicene Fathers of the Christian Church, 2nd series, vol. 9, (Edinburgh: T&T Clark, 1898), https://ccel.org/ccel/schaff/npnf214/npnf214.xiii.x.html.
 George Fisher, History of Christian Doctrine (Edinburgh: T. & T. Clark, 1894), 159.
 Thomas Aquinas, The Summa Theologica, trans. Fathers of the Dominican Province, vol. 1 (NY: Benziger Bros., 1948), 158.
 Ibid, vol. 4, 2029.
 John Calvin, Institutes of the Christian Religion, trans. Henry Beveridge (Peabody: Hendrickson Publishers, 2008), 309-12.
 William Cunningham, Historical Theology: A Review of the Principal Doctrinal Discussions in the Christian Church since the Apostolic Age, vol. 1 (Edinburgh: T&T Clark, 1863), 311-13.
 John Locke, An Essay Concerning Human Understanding¸ 27th Ed. (London: R. Griffin and Co., 1836), https://books.googleusercontent.com/books/content?req=AKW5QadzVgUJSQnk6yLoz67R2yEPTAELKlhgy61EV5UXk8zceBMQ4GjNZJXXphqD1wB7D-zMF8tTunW9C_1AIgoK9kLJAGJwcaeMDH-qIdSxqRK4EGQygLPZZPMWw_6-XksycICyZF3C9CypPe0B9O4SZGsjjXDQK6L3jqy6q_BTvtj7QrtCqkCd9Tx1l5pnR9Jhy2IuBonGm5N5xXGN3PAR6P4YHeMr2GZ2CProifdzmHANtK0LJ2IQ5-4kDEF7rSSlP6knD2tBpmUyz-EFnQhaZZBZQ4VgFibovxIf9v6l8HEnDEDoWE8, 225-226.
 Richard Muller, Dictionary of Latin and Greek Theological Terms, 2nd Ed. (Grand Rapids: Baker Academic, 2017), 263.
 James Orr, The Progress of Dogma: Being the Elliot Lectures (New York; London: A. C. Armstrong and Son; Hodder and Stoughton, 1901), 175–176.
 Ibid, 180-181
 William Lane Craig, “Does Dr. Craig Have an Orthodox Christology?” Reasonable Faith (Podcast), July 9, 2017, https://www.reasonablefaith.org/media/reasonable-faith-podcast/does-dr.-craig-have-an-orthodox-christology.