Athanasius of Alexandria’s doctrine of the deity of Christ rest upon two basic concepts. These are that the divine nature is simple and incapable of division and that the Son is generated or begotten from the essence of the Father, that divine essence which is simple. When you combine these two concepts, you get a straightforward argument: Since the Son is begotten of the Father’s essence, He possesses the fullness of that essence. It cannot be divided, and so whatever is the Father’s by nature is the Son’s by nature. He is God.
This can be seen throughout Athanasius’ writings.
In his Ad Gentes, Athanasius states that God is not composite. “For men, composed of parts and made out of nothing, have their discourse composite and divisible. But God possesses true existence and is not composite,” (Ad Gentes 3.41). This is stated rather simply, and Athanasius immediately follows it by extending this attribute to the Son of God.
He explains this further in his De Decretis:
If then any man conceives God to be compound, as accident is in essence, or to have any external envelopement, and to be encompassed, or as if there is aught about Him which completes the essence, so that when we say ‘God,’ or name ‘Father,’ we do not signify the invisible and incomprehensible essence, but something about it, then let them complain of the Council’s stating that the Son was from the essence of God; but let them reflect, that in thus considering they utter two blasphemies; for they make God corporeal, and they falsely say that the Lord is not Son of the very Father, but of what is about Him. But if God be simple, as He is, it follows that in saying ‘God’ and naming ‘Father,’ we name nothing as if about Him, but signify his essence itself. For though to comprehend what the essence of God is be impossible, yet if we only understand that God is, and if Scripture indicates Him by means of these titles, we, with the intention of indicating Him and none else, call Him God and Father and Lord. (De Decretis 5.22)
This doctrine is presumed when Athanasius criticizes those who would “ascribe divisions” to the divine nature:
…are they not mad again in seeking and conjecturing parts and passions in the instance of the immaterial and true God, and ascribing divisions to Him who is beyond passion and change, thereby to perplex the ears of the simple and to pervert them from the Truth? (Against the Arians 2.18.34)
This argument shows up again in another place:
… clearly you call God compound of quality and essence. But who will tolerate you when you say this? For God, who compounded all things to give them being, is not compound, nor of similar nature to the things made by Him through the Word. Far be the thought. For He is simple essence, in which quality is not, nor, as James says, ‘any variableness or shadow of turning.’ (To the Bishops of Africa 8)
Athanasius even extends this attribute to the whole of the Trinity. Indeed, he uses it as a way to explain the harmony between the one and the three in the divine nature:
For the Triad, praised, reverenced, and adored, is one and indivisible and without degrees (ἀσχηματιστός). It is united without confusion, just as the Monad also is distinguished without separation. For the fact of those venerable living creatures (Isa. vi.; Rev. iv. 8) offering their praises three times, saying ‘Holy, Holy, Holy,’ proves that the Three Subsistences are perfect, just as in saying ‘Lord,’ they declare the One Essence. (In Illud ‘Omnia,’ Etc. 6)
Thus, for Athanasius, the divine nature is simple. It cannot be divided. It has neither parts nor degrees. What’s more, saying this just is the same thing as saying that God is simple and that the Trinity is simple. God has no parts or degrees. The Trinity has no parts or degrees. God is Trinity.
With this basic understanding of the divine nature, we can then move on to understand Athanasius’ doctrine of the generation of the Son. To begin, we should note that Athanasius does not believe there is any meaningful difference between saying “the Son is begotten of the Father” and “the Son is begotten of the Father’s essence.” Athanasius appeals to the doctrine of divine simplicity to make this case:
If then any man conceives God to be compound, as accident is in essence, or to have any external envelopement, and to be encompassed, or as if there is aught about Him which completes the essence, so that when we say ‘God,’ or name ‘Father,’ we do not signify the invisible and incomprehensible essence, but something about it, then let them complain of the Council’s stating that the Son was from the essence of God; but let them reflect, that in thus considering they utter two blasphemies; for they make God corporeal, and they falsely say that the Lord is not Son of the very Father, but of what is about Him. But if God be simple, as He is, it follows that in saying ‘God’ and naming ‘Father,’ we name nothing as if about Him, but signify his essence itself. When then He says, ‘I am that I am,’ and ‘I am the Lord God,’ or when Scripture says, ‘God,’ we understand nothing else by it but the intimation of His incomprehensible essence Itself, and that He Is, who is spoken of. Therefore let no one be startled on hearing that the Son of God is from the Essence of the Father; but rather let him accept the explanation of the Fathers, who in more explicit but equivalent language have for ‘from God’ written ‘of the essence.’ For they considered it the same thing to say that the Word was ‘of God’ and ‘of the essence of God,’ since the word ‘God,’ as I have already said, signifies nothing but the essence of Him Who Is. (De Decretis 5.22)
Notice this line especially, “if God be simple, as He is, it follows that in saying ‘God’ and naming ‘Father,’ we name nothing as if about Him, but signify his essence itself.” Since this is the case, the expressions “of God” and “of the essence of God” actually signify the same thing.
And so, one will found countless places in Athanasius’ writings where He says that the Son is begotten of the essence of the Father. He is reluctant to explain this in full detail, but he does offer certain analogies which express his logic. One of these is the relationship between a well and a river. Athanasius says that the Father is the well and the Son is the river, and he also says that the essence of the Father “passes into” the Son:
For like as the well is not a river, nor the river a well, but both are one and the same water which is conveyed in a channel from the well to the river, so the Father’s deity passes into the Son without flow and without division. (Expositio Fidei 2)
This sort of analogy would be problematic if Athanasius did not have such a strong doctrine of divine simplicity. However, as can be seen by all of the qualifiers, he does not believe that this generation is a temporal or spatial movement. There is no actual “flow” or “division.” He is merely using the analogy of the river to imperfectly gesture towards the concept of the generatation.
This can lead to some paradoxical language, to be sure. One section earlier, Athanasius stated, “Word not pronounced nor mental, nor an effluence of the Perfect, nor a dividing of the impassible Essence, nor an issue; but absolutely perfect Son” (Expositio Fidei 1). Thus, the generation of the Son is a generation without actual movement. It does not signify time or space. There is no “distance” between the Father and Son. Athanasius will variously say that there is “no partition” and “no passion” in this generation.
Since God’s nature is “impassible” and “impartitive,” the generation of the Son is only analogically related to human generation. Whatever way that God begets must necessarily be different from the way in which men beget:
For the offspring of men are portions of their fathers, since the very nature of bodies is not uncompounded, but in a state of flux, and composed of parts; and men lose their substance in begetting, and again they gain substance from the accession of food. And on this account men in their time become fathers of many children; but God, being without parts, is Father of the Son without partition or passion; for there is neither effluence of the Immaterial, nor influx from without, as among men; and being uncompounded in nature, He is Father of One Only Son. This is why He is Only-begotten, and alone in the Father’s bosom, and alone is acknowledged by the Father to be from Him, saying, ‘This is My beloved Son, in whom I am well pleased.’ And He too is the Father’s Word, from which may be understood the impassible and impartitive nature of the Father, in that not even a human word is begotten with passion or partition, much less the Word of God. (De Decretis 3.11)
Humans are necessarily compound. God, on the other hand, is simple. Thus, He generates without division.
He also generates without a interval of time or space:
For in this again the generation of the Son exceeds and transcends the thoughts of man, that we become fathers of our own children in time, since we ourselves first were not and then came into being; but God, in that He ever is, is ever Father of the Son. (De Decretis 3.12)
In fact, Athanasius pushes this generation into the divine essence itself. The generation of the Son is “not only like, but also inseparable from the essence of the Father” (De Decretis 5.20). This generation is simultaneously the point of unity and distinction between the Father and the Son. Athanasius even goes so far to say that the divine essence is “fruitful” (Against the Arians 2.14.2)
Again, this sort of argument works precisely because of Athanasius’ understanding of the divine nature. It is a simple and infinite spirit:
Further, let every corporeal reference be banished on this subject; and transcending every imagination of sense, let us, with pure understanding and with mind alone, apprehend the genuine relation of son to father, and the Word’s proper relation towards God, and the unvarying likeness of the radiance towards the light: for as the words ‘Offspring’ and ‘Son’ bear, and are meant to bear, no human sense, but one suitable to God, in like manner when we hear the phrase ‘one in essence,’ let us not fall upon human senses, and imagine partitions and divisions of the Godhead, but as having our thoughts directed to things immaterial, let us preserve undivided the oneness of nature and the identity of light; for this is proper to a son as regards a father, and in this is shewn that God is truly Father of the Word. (De Decretis 5.24)
This argument appears again and again throughout Athanasius’ writings. It becomes almost something of a chorus in his Against the Arians:
And since to be partaken no one of us would ever call affection or division of God’s essence (for it has been shewn and acknowledged that God is participated, and to be participated is the same thing as to beget); therefore that which is begotten is neither affection nor division of that blessed essence. Hence it is not incredible that God should have a Son, the Offspring of His own essence; nor do we imply affection or division of God’s essence, when we speak of ‘Son’ and ‘Offspring;’ but rather, as acknowledging the genuine, and true, and Only-begotten of God, so we believe. (Against the Arians 1.5.16)
…Authors of blasphemy, verily, are these foes of God! who, sooner than confess that the Son is the Father’s Image, conceive material and earthly ideas concerning the Father Himself, ascribing to Him severings and effluences and influences. If then God be as man, let Him become also a parent as man, so that His Son should be father of another, and so in succession one from another, till the series they imagine grows into a multitude of gods. But if God be not as man, as He is not, we must not impute to Him the attributes of man. (ibid 1.6.21)
As we said above, so now we repeat, that the divine generation must not be compared to the nature of men, nor the Son considered to be part of God, nor the generation to imply any passion whatever; God is not as man; for men beget passibly, having a transitive nature, which waits for periods by reason of its weakness. But with God this cannot be; for He is not composed of parts, but being impassible and simple, He is impassibly and indivisibly Father of the Son. (1.8.28)
…For if in the case of these originate and irrational things offsprings are found which are not parts of the essences from which they are, nor subsist with passion, nor impair the essences of their originals, are they not mad again in seeking and conjecturing parts and passions in the instance of the immaterial and true God, and ascribing divisions to Him who is beyond passion and change, thereby to perplex the ears of the simple and to pervert them from the Truth? (2.18.34)
This point is so important because it establishes that the Son is begotten of the Father’s nature and therefore possesses that nature, that divine nature. It is because the Son is begotten from the Father’s essence that He is divine. He possesses all that is proper to that essence.
For in this rather is He shewn to be the Father’s Expression and Image, remaining what He is and not changing, but thus receiving from the Father to be one and the same. If then the Father change, let the Image change; for so is the Image and Radiance in its relation towards Him who begat It. But if the Father is unalterable, and what He is that He continues, necessarily does the Image also continue what He is, and will not alter. Now He is Son from the Father; therefore He will not become other than is proper to the Father’s essence. (Against the Arians 1.6.22)
…For must not He be perfect who is equal to God? and must not He be unalterable, who is one with the Father, and His Son proper to His essence? and the Father’s essence being unalterable, unalterable must be also the proper Offspring from it. (ibid 1.10.35)
Athanasius’ argument is consistent. God begets of His own nature– His simple, infinite, impassible nature. Thus there is not change or division involved in the generation of the Son. There is no time. And because of this there is no ontological subordination. In fact, the Son possesses the Father’s essence–the essence which cannot be divided. This means that the Son possesses the entire divine essence. He is homoousios, “…Very Son of the Father, natural and genuine, proper to His essence, Wisdom Only-begotten, and Very and Only Word of God is He; not a creature or work, but an offspring proper to the Father’s essence. Wherefore He is very God, existing one in essence with the very Father” (Against the Arians 1.3.9).
As we highlighted above, Athanasius does not merely claim that God the Father and God the Son share an abstract deity. Rather, the Son shares the Father’s own essence: “so the Father’s deity passes into the Son without flow and without division” (Expositio Fidei 2). This deity doesn’t really “pass” however, as it is by definition impassible. While admittedly grasping at words, it is because of the quality of the divine nature that this can make sense. When the Father begets in and of that nature, there is no actual movement, no separation, no “flow.” There is, rather, the Word. “If they conceive that God doth at all beget, it were surely better and more religious to say that He is the begetter of One Word, who is the fullness of His Godhead…” (To the Bishops of Egypt 2). And also, “that the Son is begotten not from without but from the Father, and while the Father remains whole, the Expression of His Subsistence is ever, and preserves the Father’s likeness and unvarying Image, so that he who sees Him, sees in Him the Subsistence too, of which He is the Expression” (Against the Arians 2.18.33).
In fact, what we begin to see is that the Son is identified with the Father’s attributes. Athanasius claims that the Son is Father’s light, the Father’s wisdom, the Father’s will, and the Father’s power:
God is light eternal, never beginning nor ceasing. The brightness then lies before Him eternally, and is with Him without beginning and ever-begotten, shining in His Presence, being that Wisdom which said, ‘I was that wherein he rejoiced, and daily I was glad in his presence at all times’ (Prov. viii. 30). (On the Opinion of Dionysius 15)
…that Word must surely be the living Will of the Father, and an essential energy, and a real Word, in whom all things both consist and are excellently governed. (Against the Arians 2.14.2)
For the Word of God is Framer and Maker, and He is the Father’s Will. (ibid 2.18.31)
…For what is sown in every soul from the beginning is that God has a Son, the Word, the Wisdom, the Power, that is, His Image and Radiance; from which it at once follows that He is always; that He is from the Father; that He is like; that He is the eternal offspring of His essence; and there is no idea involved in these of creature or work. (ibid 2.18.34)
…the Word is of God by nature Only-begotten, Power, Wisdom of the Father, Very God, as John says, and as Paul wrote, brightness of the Father’s glory and express image of His person.. (To the Bishops of Africa 5)
He is the Father’s Power and Wisdom and Word, not being so by participation, nor as if these qualifies were imparted to Him from without, as they are to those who partake of Him and are made wise by Him, and receive power and reason in Him; but He is the very Wisdom, very Word, and very own Power of the Father, very Light, very Truth, very Righteousness, very Virtue, and in truth His express Image, and Brightness, and Resemblance. And to sum all up, He is the wholly perfect Fruit of the Father, and is alone the Son, and unchanging Image of the Father. (Ad Gentes 3.46.7)
For the Son to possess divine attributes, He must possess the Father’s attributes. And since the Father is simple, if the Son possesses any of the Father’s attributes, He must possess them all. Indeed, He is all of the Father’s attributes, for He is God. Divine simplicity is an, pardon the pun, essential support for the deity of Christ:
Now, He has the prerogative of creating and making, of Eternity, of omnipotence, of immutability. Well then, if these prerogatives belong to the Son, they clearly do so, not on account of His virtue, as said above, but essentially, even as the synod said, ‘He is of no other essence’ but of the Father’s, to whom these prerogatives are proper. But what can that be which is proper to the Father’s essence, and an offspring from it, or what name can we give it, save ‘coessential?’ For that which a man sees in the Father, that sees he also in the Son; and that not by participation, but essentially. (To the Bishops of Africa 8)
… For He is His Image, and consequently, because He is His Image, all that belongs to the Father is in Him. He is an exact seal, shewing in Himself the Father; living Word and true, Power, Wisdom, our Sanctification and Redemption (1 Cor. i. 30). (In Illud ‘Omnia,’ Etc. 5)
At this point, some may want Athanasius to give a deeper explanation of how this works. To their disappointment, Athanasius says that we cannot understand it wholly, “a man must be beside himself to venture on such points; since a thing ineffable and proper to God’s nature, and known to Him alone and to the Son, this he demands to be explained in words” (Against the Arians 2.18.36). But then he adds that this “dilemma” is the same as understanding the divine nature itself, “It is all one as if they sought where God is, and how God is, and of what nature the Father is. But as to ask such questions is irreligious, and argues an ignorance of God, so it is not holy to venture such questions concerning the generation of the Son of God, nor to measure God and His Wisdom by our own nature and infirmity” (Against the Arians 2.18.36).
So again we see, Athanasius’ logic of the generation of the Son follows from his earlier definition of the divine nature as simple and infinite. Since the Son has the Father’s essence, He has all of the Father’s attributes. Or conversely, since the Son has the Father’s attributes– or since He is the Father’s attributes, He has the Father’s essence. This is true because this is the way that God is.
Highlighting these aspects of Athanasius’ thought is important because it shows that he had a certain logic about his Trinitarian theology. While he would never claim to fully understand it, Athanasius did believe that he could make some sort of rational sense the consubstantiality of the Son. It depended upon certain other theological concepts and followed directly from them, namely the simplicity of God’s essence and the generation of the Son from that essence.