It is believed too often that the Trinitarian theology of the fourth century Church was somehow innovative, without an explicit basis in the Scriptures and the ante-Nicene Sacred Tradition. On the other hand, there is also a lack of appreciation of how the Church had clarified its Trinitarian views before this point in time and how “little” fourth century fathers had to work with in devising the canonical terminology that would come to describe Trinitarian doctrine. Many fourth century saints, such as Athanasius and Hilary of Poitiers, would strictly appeal to the Scriptures due to the testimony of tradition not being clear enough to their contemporaries to address the Trinitarian issues of their day. And so, in this article, we endeavor to flesh out precisely what Trinitarian theology existed before 200 AD, because by that point in time the ante-Nicene consensus had been formed.
Hellenistic Jewish thought in the first century. When one reads Acts of the Apostles, it in many ways reads mythically. This is not only because of the supernatural elements in the account, but also the fact that a good deal of Jews “surprisingly” leave a unitarian monotheism for a Trinitarian one. Likewise, in the Apostles’ epistles, the apostles appear to take for granted that their audiences would be convinced by citations to the Old Testament (the only Scriptures that existed then) that were overtly Christological. The preceding begs the questions: Why would a Hellenized Jewish audience take for granted a Christological view of the Old Testament? What ramifications does this have upon Trinitarian theology?
By the first century, the Hebrew people have been occupied by the Grecosphere for about four centuries. Though earlier Persian influence (and its shorter two century occupation) was apparent, mainly due to the continued use of Aramaic as a spoken language, Greek influence was considerably greater. In the second century BC, there were attempts to thoroughly Hellenize the population and alter the Jewish Law, as discussed in the Books of the Maccabees.
This exposure to Greek thought eventually permeated Jewish religion. The translation of Jewish religious texts into the Greek language was chief among these. This translation was considered by the whole Jewish (and Christian) world as miraculous and infallible in its renderings, with a legend of 70 translators agreeing in every jot and tittle of the translation as proof.
Some translated texts, like Wisdom of Sirach, contained faint indications of Hellenized life in an otherwise ethnically Hebrew wisdom book. Other texts were only composed in Greek. It is with a hint of irony that the histories dedicated to the Hebrews’ victory over the Hellenists were themselves very similar to Greek histories (and in 2-3 Macc’s cases originally written in Greek). Wisdom of Solomon contained obvious elements of Aristotelian and Middle-Platonist philosophy.
Arguably, Greek thought effected the Scriptures’ translations in important ways. For example, Prov 8:22 LXX spoke of Wisdom being the “ἁρκή” (arche/origin). This term, though not necessarily latent with meaning, was used in Plato’s Timaeus 28b-c where it is a reference to “the Father and Maker of the universe.” (see p. 107-108 of this source, which is the inspiration for much of this article) It would appear to a Hellenized thinker that Jehovah begot Wisdom as completely divine. If this was not intended by the LXX translator, it was easy enough to interpret the passage as consistent with this idea.
While in Christian parlance this is often called the “baptizing” of pagan thought, the fact of the matter is to a neutral historian, this is evidence of Hellenized thought molding the Jewish religion. And so, Christ came into the world at a time when the religion of the Hebrews had already largely accepted the Hellenization of their own thought. With the exception of the Essenes (who were a small minority and had none of the Hellenized texts) and reactionary (and small) party of the Sadducees, most Jews were Pharisees (or “Pharisaically” leaning). They had an extended canon which included the Greek works and had largely evolved a system of worship which pertained more to personal faith and de-emphasized the far-away sacrificial system in Jerusalem. In fact, the whole synagogue system had pretty much evolved along the lines of providing some sort of Jewish worship among the diaspora which was not tied to sacrifices. (See here and here)
In such an environ, it should not be surprising that Judaism had begun making significant converts as a Hellene-friendly, monotheistic religion. Though the number is likely too high, mainstream scholarship asserts that about 10 percent of the Roman world was Jewish–so this would have had to include converts and a significantly large population of partially ethnic Jews, such as Saint Timothy. Hellenization within such a context is a given.
Even completely ethnic Jews openly interpreted the Scriptures in an overtly Hellenized sense. For example, Philo of Alexandria interpreted the Book of Genesis along Middle-Platonic emanationist lines. For those who do not know, emanationism is the Platonic view of creation sourcing itself from an involuntary act of a transcendent ultimate deity, which within itself contains the archetype of all things, and as a sort of imaginative echo these things come into metaphysical and then physical existence. With each echo itself echoing, this leads to the essence of the echoes increasingly altering from the essence that preceded them. And so, the emanations are in effect created and different in essence from the transcendent deity.
Philo appears ready to accept this Platonic view, but at the same time he is sincere in his devotion to Judaism. He speaks of “the Father” (a name for God from Plato’s Timaeus, but it is also used in Is 63:16 MT/LXX) being the chief God and the Logos/Word, known in Rabbinic literature as “Memra,” being “the second deity.” The Word, while not being as supreme and incomprehensible, is both God (being from Him), but also lesser in some sense so that it is possible that man can be made in His image. In Philo’s own words:
[N]o mortal thing could have been formed on the similitude of the supreme Father of the universe, but only after the pattern of the second deity [lit. “deutero theos”], who is the Word of the supreme Being; since it is fitting that the rational soul of man should bear it the type of the divine Word; since in his first Word God is superior to the most rational possible nature. But he who is superior to the Word holds his rank in a better and most singular pre-eminence, and how could the creature possibly exhibit a likeness of him in himself? (Answers to Genesis 2:62)
As one can see, calling this lesser God “the Word” makes sense as He makes God intelligible (He is not categorically transcendent as an image can be made of Him). Philo, though consistent with Platonists (who postulated a lesser-deity called the Demiurge that was an aforementioned “echo” which created the material universe), is not exactly wedded to Platonism in every respect. He does not go as far in really separating the Father from the Word. It is as if he lacks the terminological distinctions to explain they are one God, but two people. Additionally, he may have viewed the runaway emanationist view as not explicitly Scriptural enough to adopt without qualification.
One indication of the preceding is that in another exegesis of the Book of Genesis, Philo makes the assertion that the Word Himself is also (mostly?) transcendent. He is God after all. In making this point, Philo also asserts the existence of another lesser deity, the “Breath of God”:
And air and light he considered worthy of the pre-eminence. For the one he called the breath of God, because it is air, which is the most life-giving of things, and of life the causer is God; and the other he called light, because it is surpassingly beautiful: for that which is perceptible only by intellect is as far more brilliant and splendid than that which is seen…[T]he invisible divine reason, perceptible only by intellect, he [Moses] calls the Image of God. And the image of this image is that light, perceptible only by the intellect, which is the image of the divine reason, which has explained its generation (On Genesis, v. 30-31)
Contrary to Philo, in the LXX the “Breath of God” is not implied to be inferior to the other Persons of the Godhead in any way: “[By] the Word [lit. The Logos, τω λογω] of the Lord the heavens were established; and all the host of them by the Breath [lit, the Spirit, τω πνευματι] of the mouth of Him.” (Ps 32:6 LXX) And so, the usage of the definite articles in the Greek appear to equate the Word and Spirit as two Persons equally responsible for creation. It is clear that Philo recognizes this, but also intentionally Hellenizes the preceding to make his cosmology more Middle-Platonist, which has inherently unequal emanations with each subordinate to the next. In Middle Platonism, there is no explicit equality between the Logos and transcendent God, let alone the Logos and some other divinity.
Additionally, there is an emanationist streak in Philo’s thought which makes the divine more intelligible. While the “Image of God” is clearly deity, the way He is apprehended is only by intellect, because we cannot apprehend God in His essence. What humanity apprehends is an “image of this Image.” From this, we can glean not only an implicit energy-essence distinction, but also in keeping with emanationism the Word/Image of God is apprehended not in His true essence but in the form of some lesser emanation, here called “light.”
And so, it appears that Philo’s Jewish and Middle Platonist sympathies melded his thought into something of a henotheistic binitarianism, with two gods who are in fact one God and lesser emanated deities, which includes chief among them the Spirit, which is subordinate to God the Father (v. 89) and His Image. The Spirit/Breath’s role is to act as the sustaining force that upholds all of creation:
[T]he breath of the Deity, by which the whole universe obtains security at the same time with the calamities of the world, and with those things which exist in the air, and in every mixture of plants and animals. (De Profugis, v. 288)
Those who are mindful of early Christian movements such as Gnosticism may notice that the distance between Philo’s and the Gnostics’ cosmologies are terrifyingly close. And so, the Gnostic worldview of one chief inaccessible God (Bythus, Propator, etcetera) made apparent by an emanation that makes Him known (i.e. Nous), and then additional emanations may seem silly to us. However, it was downright sensible to educated, Hellenistic-Jewish audiences. Understanding Christianity as within the realm of Hellenized Judaism makes sense of Gnosticism’s initial appeal as Hellenized Jews, many of who became the early Christians, would have desired a more overtly Platonic religion.
Nevertheless, as mentioned beforehand, Philo was not strictly a Middle Platonist. While affirming the Word as God as different from the Father, he also affirmed the existence of only one God. Additionally, he appears to ascribe the omnipresence of God to an emanation, the Breath/Spirit of God. And so, there is an obvious latent Trinitarianism in Philo’s thought hidden among a Judaized Middle-Platonist, emanationist muddle.
This muddle creates other obvious errors. In On Genesis (v. 72-75) Philo teaches that God did not make man alone, because man is not always good. Man was made with some other beings (who they are is not said, but they are likely the Word’s Light and Breath working with angels) so they can bare the blame for anything bad that man does. This implies man was defective before the Fall. And so, in his attempt to uphold the plain meaning of the Scriptures (“we should make man according to our icon [i.e. image]…God according to God’s icon [image] God made him,” Gen 1:26-27 LXX, cf Wis 2:23), Philo tried to infer man was made is some lesser image of the chief deity—man in fact being made in the image of “God’s image” (i.e. the Word, not the Father). This Platonizing had in effect distanced his views (here, anthropology) from literal Scriptural views (which imply no defects in humanity before the Fall).
The teaching of the Apostles. When the Apostles spoke of Christ, they did not shy away from the language of Philo and his contemporaries. Saint John spoke of Jesus as “the Word made flesh” (John 1:14) who made God the Father known (John 1:18) and Saint Paul called Him “a great high priest” (Heb 4:14), a connection not just strictly allegorical in it Scriptural merits but also consistent with how contemporary Hellenistic Judaism viewed the Word. Philo in describing the high priest conflated him with the Word: “The high priest is not a man, but is the word of God.” (De Profugis, v. 108) Philo likewise believed in the utter transcendence of the Father, necessitating the Word to make God known.
Not surprisingly, the Apostles had a Trinitarian bent similar to Philo, but without reference to emanationism. This is evidenced by their Trinitarian baptismal formulas (Matt 28:19), Trinitarian blessings (2 Cor 13:14), and obvious personifications of the Son and Spirit (Mark 3:29, Luke 3:22, Acts 5:3, Heb 3:7) as mutually exclusive people treated as God. This exhibited continuity with pre-Hellenistic Jewish thought as the Scriptures plainly called (at least) two persons God (i.e. Ps 110:1 MT), books like Job clearly spoke of God mediating between man and God, and treatments of the Holy Spirit as both God and a Person (Is 63:10-11, Wis 1:7). If anything, the Apostles in their actual writings were unremarkable and literal in repeating the earlier Scriptural teaching and not further elucidating upon it.
The only early church sources perhaps contemporaneous with the Apostles are the Didache and 1 and 2 Clement, but they simply reiterate the “painfully plain” Trinitarianism of the Scriptures and Apostles with no additional clarification. Saint Clement quotes the Holy Spirit as a speaker similar to the Epistle to the Hebrews (1 Clem 13, 16, 22), calls Christ God (1 Clem 2 in reference to God suffering, 2 Clem 1 asserting that “you should think of Jesus Christ as of God”), and makes a Trinitarian blessing (1 Clem 58). The Didache reiterates the Trinitarian baptismal formula (chap 7), likewise treats the Spirit as both a Person and God (chap 4), and quotes Matt 21:19 (“Hosanna to the son of David!”) as “Hosanna to the God of David,” (chap 10) an obvious assertion of Jesus’ deity.
The earliest post-apostolic sources written sometimes exhibit this bare Trinitarianism. One example is Saint Ignatius, allegedly the Apostle John’s disciple, in Epistle to Magnesians, Chap 13. However, in Ignatius there is evidence that the Apostles had affirmed a somewhat more drawn out Christology. In one letter he makes an interesting creedal affirmation:
There is one only physician, of flesh and of spirit, generate and ingenerate [lit. “begotten and unbegotten” γεννητὸς καὶ ἀγέννητος], God in man, true Life in death, Son of Mary and Son of God, first passible and then impassible, Jesus Christ our Lord. (Epistle to Ephesians, Chap 7)
The statement “generate and ingenerate” appears to be a parallelism with “flesh and spirit,” flesh being “generate” and the spirit of Christ (i.e. His divine essence, because “God is spirit” according to John 4:24) being ingenerate. Hence, Ignatius is asserting that Christ in His divinity is eternal. Christ is not an emanation or highly ranked angel. He is plainly eternal God.
The fact the preceding creedal affirmation is creedal means that it predates Ignatius. The creed may very well be a repetition of the Apostolic witness. Later Christological doctrinal clarifications, which speak of Christ’s eternal generation, would lead to the snuffing out of speaking of Christ’s “ingenerate-ness.” Saint John of Damascus, when calling Christ “unoriginate [ἄναρχος] and begun [καὶ ἠργμένος]” uses different Greek words, simply because of the changing emphasis upon the significance of Christ’s eternal generation and the change in the technical meaning of “γεννητὸς.” In any event, the creed of Ignatius is for interpreters good evidence that the Apostles without any obscurity taught that Christ was eternal God.
And so, what the Scriptures, Apostles, and contemporary writers have in common, as opposed to Philo, is a naked Trinitarianism without much elaboration. Three Persons are treated as both mutually exclusive and one God—that’s about it with perhaps the exception of Ignatius’ creedal affirmation. It is never explained how this exactly works, other than passing references to the Son being begotten or the Spirit proceeding from the Father. The deity of the Holy Spirit, though asserted, is done so obliquely and never plainly.
It is said of “Christ as concerning the flesh, who is over all, God” (Rom 9:5) or “our great God and Savior Jesus Christ.” (Tit 2:13) Elsewhere the Scriptures are likewise clear concerning Christ’s deity, admonishing bishops to “shepherd the assembly of the Lord and God which he purchased with His own blood.” (Acts 20:28; cf Ignatius, Eph 1, Chap 1 where he invokes the “blood of God” in reference to Jesus.) Why is the Holy Spirit called plainly God in unequivocal terms such as the above? Ultimately, this is a mystery. In any event, the lack of clarification caused some confusion as early teachers in the Church tried explaining with more precision what Christians believed in subsequent centuries.
Second century elucidations of Trinitarian doctrine. Perhaps the earliest extant work with some explanation of the Trinitarian doctrine of the Apostles was The Ascension of Isaiah.* The work has a proto-Gnostic cosmology, with the Father being the chief God, and the Son and the Spirit being lesser “angels” still worshiped as God. (8:34-40)
*This dating is due to it sharing certain similarities with 1 Clem in 1:22-24 and the Book of Revelation in 7:21. Yet, it is seemingly dated after 3 John as evidenced by 1:27, 29.
Such speculations, though clearly consistent with the worldview of contemporary Jews and seemingly consistent with Jewish angelology, Middle Platonism, and the bare Trinitarianism of the Apostles, were to a more careful observer beyond the plainly revealed teaching of the Church laid out above.
Without a more explicitly fleshed out Apostolic teaching, early saints of the church (generally called “the apologists”) likewise sometimes made less than ideal clarifications upon the Trinitarianism of Apostolic tradition. These writers dialed back the henotheistic speculations of early Judaism and Ascension, and if they erred, it was always on the side of the biases of their audiences. In other words, these fathers were not as much wrong as misunderstood by post-Nicene interpreters far away from their apologetic concerns and the needs of their time.
This makes sense given the fact the audience for these early works were not Christians. These were apologetic works written for pagans and Jews with the intended purpose of convincing them of a foreign, then fringe, idea. No one wants to appear as fringe, of course, and so things were deliberately worded in ways that would be “mainstream” for their era. The LutheranSatire video about Saint Patrick’s (my patron saint) allegedly bad Trinitarian analogies is a good example how someone can try to teach a true doctrine, but end up wording it imperfectly.
In Saint Justin Martyr’s case, he is accused of Christological subordinationism by the Catholic Encyclopedia due to how he explains the differences between the Father and the Son. Concerning the latter’s generation, those who accuse Justin of subordinationism allege he implies that Jesus is less than God. However, if one reads the actual passages cited, Justin never explicitly says this.
Rather, when one does not put too much emphasis on the occasional weakness (though never outright false) explanations Justin gives, one may infer that he is trying to communicate orthodox Trinitarianism. At the very least, the practices of the Church recorded in Justin betray a fidelity to the Apostolic teaching. In Justin’s words: “[B]oth Him, and the Son (who came forth from Him and taught us these things, and the host of the other good angels who follow and are made like to Him), and the prophetic Spirit, we worship and adore.” (First Apology, Chap 6) Likewise, Justin treats Jesus Christ as well as the Holy Spirit as God and different Persons when quoting Old Testament passages. Therein, he cites both of Them speaking. He also condemns heresies such as modalism (“they who affirm that the Son is the Father”). (Ibid., Chap 63) Justin was neither unitarian nor binitarian.
Being that the doctrine of the Trinity was not then drawn out, it made sense that Justin would cast Trinitarian doctrine in a sense familiar with Middle-Platonist thought as this is was the intellectually-respectable lens that both pagan and Hellenistic Jewish audiences understood their own religions. However, Justin is not in fact a Middle Platonist. He does not teach emanationism and correctly understood, nothing he says makes Christ a creature, nor contradicts His eternally-begotten origin.
In fact, there is nothing Justin teaches that is necessarily inconsistent with the Nicene-Constantinopolitan doctrine of one God being of one essence in three Persons. In fact, Justin asserts that the Son “is indivisible and inseparable from the Father…begotten from the Father, by His power and will, but not by abscission, as if the essence of the Father were divided.” (Dialogue with Trypho, Chap 128) This implies that he well understood Christ to be a different Person but of the same essence—precisely the Nicene confession.
Contemporary Christian apologists were similar to Justin in maintaining the Apostolic teaching in a sense entirely consistent with the mature Nicene Trinitarian consensus, though they likewise exhibited Middle-Platonic biases in clarifying matters to their audiences. Those who too seriously imbibed in philosophy, like Justin’s disciple Tatian, became Gnostics as Gnosticism’s cosmology was more strictly consistent with Platonist emanationism.
Even before Justin, Saint Aristides (an apologist from the early-second century, he was contemporaneous with the Emperor Hadrian), defended early Trinitarian doctrine in a sense consistent with fourth-century Orthodoxy. Concerning the divinity of Christ, he wrote, “God came down from heaven, and from a Hebrew virgin assumed and clothed himself with flesh.” (Apology, Chap 2) Additionally, he asserts, “God is one in His nature. A single essence is proper to Him, since He is uniform in His nature and His essence” and denies this truth applies to the pagan gods. (Chap 13) This appears to be a clear assertion that the Father and Son are two people, but one divine nature/essence.
The preceding shows that before the year 130 AD Christological doctrine was already clarified in terms no less equal than the Nicene Creed, and the only doctrinal clarification lacking was that of the Persons being “particular hypostases,” something elucidated by the Cappadocian fathers after Nicea. However, the teaching of three Persons being the same God according to nature/essence is, fundamentally, an equivalent teaching. Even though the Apostles never explicitly connected the dots between God, Person, essence, and hypostasis, these dots were meant to be connected and were easy to connect. Only about 60 years after the Apostolic era, Aristides specifically elucidates Christology consistent with Orthodox Trinitarianism.
A few decades later, Saint Athenagoras asserts a similarly well-clarified Trinitarian worldview. He teaches that, “He is God who has framed all things by the Logos, and holds them in being by His Spirit.” (Plea for the Christians, Chap 6) Likewise, he appears to hold to the hypostatic differences between divine persons (showing skepticism of pagan claims in this regard in Ibid.) and on this note asserts that “it would be irrational for us to cease to believe in the Spirit from God.” (Ibid., Chap 7) With more than a tinge of Middle-Platonist thought, Athenagoras then describes the origins of the divine Persons while affirming They are one God:
[T]he Son of God is the Logos of the Father, in idea and in operation; for after the pattern of Him and by Him were all things made, the Father and the Son being one…He is the first product of the Father, not as having been brought into existence (for from the beginning, God, who is the eternal mind [νοῦς], had the Logos in Himself, being from eternity instinct with Logos [λογικός])…The Holy Spirit Himself also, which operates in the prophets, we assert to be an effluence of God, flowing from Him, and returning back again like a beam of the sun. Who, then, would not be astonished to hear men who speak of God the Father, and of God the Son, and of the Holy Spirit, and who declare both their power in union and their distinction in order, called atheists? (Ibid., Chap 10)
And so, Athenagoras clearly asserts three Persons to be one God. This, he asserts, is the common belief of all Christians:
[T]hey know God and His Logos, what is the oneness of the Son with the Father, what the communion of the Father with the Son, what is the Spirit, what is the unity of these three, the Spirit, the Son, the Father, and their distinction in unity. (Ibid., Chap 12)
[W]e acknowledge a God, and a Son his Logos, and a Holy Spirit, united in essence — the Father, the Son, the Spirit, because the Son is the Intelligence, Reason, Wisdom of the Father, and the Spirit an effluence, as light from fire. (Ibid., Chap 24)
While one may infer a Platonic subordination of the Spirit to God and the Logos (as They may be the combined “fire” in the metaphor), this only speaks to the weakness of allegories and Athenagoras being hamstrung by sticking with concepts the audience understands. Nevertheless, he explicitly states like Justin and Aristides that the Son shares the same divine essence as the Father. In addition, he includes the Holy Spirit as one in essence with Them.
Saint Theophilus of Antioch is likewise Trinitarian. He asserts his belief in “one God” (To Autolycus, Book 1, Chap 4) who “alone” created the universe. (Ibid., Chap 7; cf Is 44:24) The Word of God is called the ἁρκή (arche/origin) of creation and the “Spirit of God” is plainly called “God.” It is clear that the Son and the Spirit are mutually exclusive: “God, then, having His own Word internal within His own bowels, begot Him, emitting Him along with His own Wisdom [i.e. Spirit] before all things.” (Ibid., Book 2, Chap 10)
Saint Irenaeus is similar to Theophilus in referring to the Spirit as “Wisdom” and in making references to God’s “Hands,” the Son and Spirit. (Ibid., Chap 18) Using wording that is more explicit than Irenaeus, Theophilus asserts that these Persons are the Holy Trinity: “In like manner also the three days which were before the luminaries, are types of the Trinity, of God, and His Word, and His Wisdom. And the fourth is the type of man, who needs light, that so there may be God, the Word, Wisdom, man.” (Ibid., Chap 15) The preceding shows that Theophilus understood the Book of Genesis similar to Philo, but by calling the “light” and such luminaries “types” (i.e. literal creations which metaphorically represent God the Word, and God the Spirit) he avoids the overt emanationism of Philo (which reduced the luminaries to names of Aeons/emanations of God). Eusebius asserted that Theophilus wrote a work against Marcion (see Ecclesiastical History, Book 4, Chap 24), which may explain why Theophilus would “un-platonize” the allegorical view of Genesis in this regard.
Theophilus, despite being so careful to correct Hellenistic error, is ironically the only saint in the early Church to say something that is so overtly Middle Platonist that it borders on heresy. In speaking of the Son’s eternal generation, he states:
For before anything came into being He had Him as a counsellor, being His own mind and thought. But when God wished to make all that He determined on, He begot this Word, uttered, the first-born of all creation, not Himself being emptied of the Word [Reason], but having begotten Reason, and always conversing with His Reason. (Theophilus of Antioch, To Autolycus, Book 2, Chap 22)
The word “but when” seems to imply a creation in time, with the Word’s existence contingent upon the Father’s will to initiate creation and the space-time continuum. Possibly implicit in this is the Middle-Platonist idea that the Father is utterly transcendent and the Word is a step down in transcendence, and so capable of interfacing with the created order in a way the Father cannot. Given that there is no literal “when” before time, Theophilus may be forgiven–but clearly such words can be taken the wrong way. (It is unbeknownst to the author if the Arians cited Theophilus or if many of his works were lost due to formulations such as the above that sounded too much like Arianism.)
Centuries later, other saints such as Augustine likewise struggled to speak of eternal causality within the Trinity without chronological terms which are admittedly deficient. In Augustine’s case, the question was over the Father’s aseity. Can the Father be the Father, and have a Logos within Himself, without the Personhood of the Son? In short, no, though this is a particularly difficult question and one can wrongly infer the Father as having aseity (and the Person of the Son being something coming from the will of the Father without the necessity of His generation) from statements of saints like Theophilus and Augustine. And so, the preceding demonstrates how the saints are trying to reiterate Scriptural and Apostolic ideas, but in so doing were being cognizant of the philosophical language of their time, sometimes tinging their ideas with Platonist concepts.
As one comes to the end of the second century, the figure that looms especially large is Irenaeus. However, due to his doctrine of the Trinity being more strictly Scriptural (and not parsing out the ramifications of the Apostolic doctrine using the Middle-Platonist paradigm of his time), much of what he has to say in light of what has already been discussed is unspectacular and, in fact, redundant. He simply reiterates what the Scriptures and Apostles taught without elaborating upon their teachings. Nevertheless, he makes one particular statement of note in Book 3, Chap 24, Par 2 of Against Heresies:
[T]hrough His love and infinite benignity, He has come within reach of human knowledge (knowledge, however, not with regard to His greatness, or with regard to His essence— for that has no man measured or handled — but after this sort: that we should know that He who made, and formed, and breathed in them the breath of life, and nourishes us by means of the creation, establishing all things by His Word, and binding them together by His Wisdom — this is He who is the only true God). (cf Ibid., Book 1, Chap 22, Par 1)
From the preceding, one can infer several important things. First, God is not known in His essence by man, but by “benignity” or His grace in creation. This is clearly the energy-essence distinction at work. Second, we see that this essence is made known in creation by three Persons: “Him,” “Word,” and “Wisdom.” In other words, the Father, Son, and Holy Spirit are of all one essence and we know this tri-personal God by His grace or energies, not by His actual essence.
By the turn of the century, debates have generally shifted away from the concerns of Hellenized Judaism (including Gnosticism) and polytheistic Paganism. Instead, apologetic works aimed against heretical Christians, particularly modalism and proto-Arianism, the latter’s theology making Christ less than divine. For example, Caius, an early priest in Rome living at the turn of the century, asserted that “Irenaeus and Melito, and the rest, which declare Christ to be God and man” and denounced “Theodotus the tanner” who asserted “Christ was a mere man,” recalling that Saint Pope Victor I excommunicated him for this belief. (Eusebius, Ecclesiastical History, Book V, Chap 28)
These debates would lead to some odd, heretical Trinitarian speculations from Tertullian (not covered here) and further elucidations from Saint Hippolytus, but not necessarily advances in Trinitarian doctrine. All the crucial advances have already been made. Quite frankly, the second century fathers had already affirmed all of the Nicene-Constantinopolitan distinctives in one way or the other, so that Saint Vincent of Lerins centuries later could say with no disingenuousness that all non-Trinitarian doctrines were obvious innovations.
Conclusion. From the preceding, one can conclude that Trinitarian theology is Scriptural. Generally, the Jews grappled with this theology using Middle Platonism and ever since then, rabbinic Judaism’s Gnostic cosmology has been plagued by the ramifications of this.
To the contrary, the Christian apostles appeared to innocently reiterate basic, Scriptural Trinitarianism—likely the popular belief of the Jewish laity. When the time came to further explain how this worked, the Christian apologists of the second century tended to resort to the same philosophical background that their Jewish predecessors did. Yet, by the grace of God, they were much more faithful to their faith tradition and avoided devolving into Platonist henotheism as the Jews did. They affirmed the equality of essence of the Persons of the Trinity and the distinctness of these Persons. Therefore, the Trinitarian understandings of the Councils of Nicea and Constantinople were not fourth century novelties, but were in fact a reiteration of a hardened consensus from the earliest times in Church history.