The unity of Christ in Cyril of Alexandria's Festal Letters

Abstract

Cyril of Alexandria's Festal Letters are an underutilised source of his theology. Through them one can trace the development of his thought throughout the tumultuous years of his episcopacy. In this article, I draw attention to Cyril's ‘unitive’ Christology and the way he explains the incarnation to those under his pastoral care. Cyril employs key strategies informed by strong theological convictions to describe Christ as one subject who is fully divine and human.

Cyril, bishop of Alexandria from 412 until his death in 444, is regarded in Christian history as the ‘seal of the fathers’. He lived in a pivotal era when the church was consolidating political and cultural power throughout society, yet struggling internally through doctrinal controversy and ecclesiastical wrangling to convey a unified, coherent and faithful witness to the person and work of Jesus Christ. Cyril's contribution to the church's theology during the Nestorian crisis of the fifth century is regarded in much of Christendom as the standard of orthodox Christology against which all subsequent christological developments are evaluated.¹ Through careful and often painstaking exegesis of Scripture, firm theological convictions, effective language and wise (or, perhaps shrewd) political calculations, Cyril helped the church articulate its central message that the eternal Word and Son of the Father became flesh in the person of Jesus Christ to triumph over death and transform human nature.

Cyril's own Christology had to develop throughout the christological debates that consumed much of his energies during the second half of his bishopric. Against a dualistic or so-called ‘two-sons’ Christology that separated the divine Logos from the human Jesus, Cyril stressed the unity of Christ's person that preserved his deity and humanity. For this reason, much scholarship has been devoted to Cyril's dogmatic and polemical treatises written from 428 – the year he first took notice of Nestorius – until the end of his career.² These works continue to garner keen interest, as they clearly exhibit the breadth and sophistication of Cyril's Christology, as well as other key doctrines within his theological schema.³ They also manifest his penchant for disputes and political manoeuvring, a character defect noted by ancient and modern critics alike. In recent decades, increasing scholarly attention has been given to Cyril's interpretation of Scripture through new translations of his commentaries, along with studies of his interpretive methods and the theological insights that arise from his reading of Scripture.⁴ This has been a welcome development in Cyrilline scholarship. But to date far less focus has been dedicated to the pastoral works of Cyril known as the Festal Letters.⁵ The Festal Letters were annual correspondences written every autumn by the Alexandrian bishop to Christians throughout Egypt announcing the dates of the Lenten fast and Easter Sunday for the following spring. This practice began in the late second century with bishop Demetrius.⁶ Originally, letters were brief, in keeping with their purpose; but over time, they took on greater length and significance as bishops began using them as teaching tools for discipleship and theological instruction.⁷ Cyril follows this trajectory. He used his Festal Letters as occasions to articulate doctrines, demonstrate proper exegesis of Scripture, warn against false teachings and encourage believers to pursue holiness. All twenty-nine letters from Cyril have been preserved. For this reason, the Festal Letters are an invaluable resource to gauge the development of Cyril's thought as well as his pastoral sensibilities. In fact, these letters reveal that for Cyril pastoral ministry and theological convictions coinhere.

One of the fruits of studying the Festal Letters is that through them, we get a portrait of Cyril as the shepherd and overseer of souls. This helps provide a more balanced perspective to a reputation often shaded by his pugilism and hostility towards his adversaries.⁸ In addition, because the dates and chronological sequence of these letters are known, one can get a reasonable sense of the particular historical, political and cultural events occurring in Cyril's Alexandrian milieu when he wrote them, as well as any developments or shifts in his thinking as the successive years of his ministry wore on through changing circumstances and new challenges.

My aim in this essay is to explore Cyril's doctrine of the person and work of Christ in the Festal Letters. These letters are Cyril's pastoral attempts to communicate the mystery of the incarnation to those under his spiritual care. Thus, I will draw attention to the scriptural, theological and linguistic tools he utilises to help the believers under his care rightly confess the mystery of Christ. I will also point out the theological convictions embedded within these letters that provide a theological framework for Cyril's teaching. As I will show, his concern throughout the letters is to articulate a unitive doctrine of the incarnation that distinguishes but does not divide the divinity and humanity of Christ. Jesus Christ is the person of the Son who became man. Further, the Festal Letters provide a panoramic view of Cyril's Christology from the beginning of his bishopric, throughout the years of the Nestorian controversy, the Council of Ephesus and its aftermath, until the end of his life. Though there are some developments in his terminology, the letters convey a remarkable consistency in Cyril's Christology over his long episcopal career. The consistent Christology of the letters mirrors the christological convictions one finds elsewhere throughout Cyril's corpus. Thus, the Festal Letters do not so much convey new or different ideas in Cyril's theology as confirm what he expresses about the mystery of Christ in his exegetical and polemical writings. Given their under-utilisation as a source for Cyril's theology to this point, my hope is that this study will not only contribute to the growing body of scholarship on Cyril, but will encourage more studies of his Festal Letters in particular.

Communicating the mystery of the incarnation

Cyril's Festal Letters convey the bishop's effort to instruct believers throughout Egypt about how they should understand and confess the incarnation. His primary concern is that they know Jesus Christ is the divine Son of God who became man while remaining what he had always been from eternity. That is, the Son who pre-existed with the Father is the same one who was born of the Virgin Mary and ‘became obedient to death’ (Phil 2:8) for our salvation. Cyril's central thesis is that Jesus is truly divine and truly human as one, whole, undivided person.⁹ His emphasis is thus on a ‘unitive’ Christology. Jesus Christ is not the divine Word alongside a separate man with whom he shares the same body. Rather, Cyril declares Jesus Christ is one subject; the divine person of the Son – one of the consubstantial Trinity – who became man. Cyril employs four important strategies throughout the Festal Letters to explain his unitive Christology.

The first strategy is Cyril's constant reminder to his readers, perhaps to their relief, that the incarnation is a mystery beyond human ability to fully comprehend. What one believes by faith is not always what one can fully grasp with the mind. In his very first Festal Letter, the new bishop observes the incomparable distance between human nature and the divine nature of the Logos. The Scriptures declare that humans are ‘dust and ashes’; but concerning the Son, the prophet Isaiah asks, ‘who will be able to explain his generation’?¹⁰ The glorious incarnation is a mystery according to the prerogative of God. As Cyril remarks in his twelfth letter, humans confess and worship God, but they cannot know the divine nature itself.¹¹ The union between the incomprehensible divine nature and the human nature we experience is something both unfathomable and wonderful for Cyril. In his tenth letter, he observes that the divinity and humanity of Christ are bound in an ‘ineffable combination’ (ἀρρήτῳ τινὶ συνόδῳ), where both are distinguished in concept alone.¹² His eighteenth letter, written for 430, is another example where Cyril maintains that the divinity and humanity of Christ come into union ‘ineffably’ (ἀποῤῥήτως) and in a manner ‘beyond comprehension’.¹³ That is, the Word's natural deity and his assumed humanity are so singularly united that only by logical inference can one distinguish between them.

The second strategy Cyril uses to explain his unitive Christology is his firm and repeated warnings against ‘dividing Christ in two’. Cyril admonishes against speaking or thinking about Jesus Christ as if he is the product of the divine Son possessing or inhabiting a human being, thereby making Jesus two entities that only appear to be unified through a single human body. He also warns against the notion that the Son of God was transformed into a human person, as though the eternal Word could abandon his divine state and change into another condition altogether, resulting in one Son before and another Son after the incarnation. Though Cyril's insistence on Christ as one subject – the divine Son as man – became prominent in his struggles with Nestorius and his allies, and would be the christological hallmark for which he is remembered, his warning against a doctrine of ‘two Sons’ appears well before the controversy arose.¹⁴ In his eighth letter, written for 420 – years before he became aware of Nestorius’ controversial teachings – Cyril is preoccupied with proving that the Son of God is one and the same before and after taking flesh. His point is that the eternal Word does not undergo change even though he became man. Cyril finds support from Heb 13:8: ‘Jesus Christ is the same yesterday and today and forever’. A critical interlocuter may pose the question, ‘If Jesus was a man born “in these last times”, how has he always been’? Cyril answers that Paul (like nearly all the fathers, Cyril believed Hebrews to be Pauline) attributes to Christ's humanity ‘the things belonging to the Word, who lives and is forever’. To do otherwise would be ‘to divide in two…the one, only, and true Son’ after the incarnation.¹⁵ Cyril elaborates:

The things that properly and naturally belong to the Word, even before the flesh, are also the things attributed again to him when he had become flesh, knowing that he has not become other on account of the flesh, but the honor of divinity is preserved in full for him even when he became man.¹⁶

Here we see an early articulation of the communicatio idiomatum from the young bishop. What is true of the divine, eternal Son can be attributed to the man Jesus Christ who is that very same Son in the flesh. Commenting on Col 1:14–18, Cyril remarks,

For in the same way as it is not thought suitable to a human being to create, which does suit God, so also is it foreign to God to die. But apparently Paul applies both to the same One. For he does not know of one Son and another, but One and the same.¹⁷

Jesus Christ is ‘one both before flesh and with flesh’.¹⁸ To be sure, Cyril recognises the ontological difference between the divinity the Son has always had and the human nature he assumed.¹⁹ Deity is one thing and humanity quite another. But in the incarnation ‘there is one Christ from the two’.²⁰

Cyril presses this conviction with greater force in Festal Letter 17, written for 429. At this point, he had become embroiled in the debate with Nestorius. With his adversary in mind, Cyril charges,

…he who places parts in front of us, presenting both a man and another son separately from the one who is from God by nature, does not accurately comprehend the depth of the mystery. For it is not a man we have worshipped and have learned to obey from the saints who instructed us in the divine mysteries, but, rather God has become man…and the Word who is from the Father is regarded as one with his own body.²¹

As in Festal Letter 8, written nine years previously, here, too, Cyril is concerned to preserve the divine immutability of the Son. Even when the Son became flesh, he did not abandon the ‘natural dignities inherent in him…the only-begotten Word of God did not become man in order to cease to be God, but rather that even in assuming the flesh, he might preserve the glory of his own excellence’.²² In remaining what he had always been even when becoming man, Christ elevated human nature in himself to an honour suited to the divine.²³ We worship the one incarnate Son who, through ‘interweaving’ (ἀναπλέκοντες), is both divine and human. The eternal Son experienced a human birth through the holy Virgin. For this reason, we do not regard him as a man who bears God, but ‘as God who has become man’.²⁴ Cyril warns against conceptualising the ‘one Christ and one Lord’ as being ‘cut up’, resulting in a man apart from God after the incarnation.²⁵ Though the human and divine natures are incomparably different from one another ontologically, Cyril insists that the church accepts and apprehends the incarnate Christ as ‘one Son’.²⁶

Cyril provides an illustration of the union of divine and human in Christ using the image of a costly jewel penetrated by beams of light.²⁷ As the beams radiate through the jewel, a beholder would observe the illumined stone as a single object. Cyril maintains that the union of jewel and light can be divided only in the abstract. That is, one can conceive of the precious stone as a thing in itself apart from the light within it, and vice versa. But if the radiant jewel is shattered, the singleness of the entity is likewise destroyed. The result is the separation of the union of light and stone. Cyril decries this separation as ‘unacceptable’, since a single, beautiful entity has been ruined through division. Cyril then makes the obvious christological application.²⁸

And thus we speak also of Christ: in an ineffable way that one can neither know nor explain, divinity and humanity have come together in one place, to what ultimately is regarded as one, so that in this he is considered both man with us and God for us; both the only-begotten and firstborn.²⁹

Even though one can conceive of Christ's divinity separate from his humanity, in reality they are inseparably united in him and cannot be otherwise.

The third strategy Cyril uses to describe the unity of Christ is his careful application of biblical language. He is especially indebted to John 1:14 and Philippians 2:6–8. Cyril quotes or alludes to both passages with steady frequency throughout the letters and seeks to wed them together into one coherent message.³⁰ In the Johannine passage, he pays particular attention to the word ἐγένɛτο (‘became’): the Word became flesh.³¹ Cyril is adamant that the Son was not ‘in’ a human being; that would call into question the uniqueness of Christ, since the Word dwells in all the saints.³² Christ was not a man ‘possessed’ by divinity; that would indicate a merely deified man.³³ The Son did not mysteriously transform into the nature of the flesh; that would indicate a change in the divine nature.³⁴ Cyril also admonishes that the eternal Son did not ‘join (συνάψας) to himself a human being’.³⁵ That would mean Christ is two, a strange amalgamation of the divine Son and a human person. Rather, the eternal Son who is consubstantial with the Father became man in a way that surpasses understanding.³⁶ Though the manner of the incarnation is mysterious, Cyril points to the kenosis, or self-emptying, of the Son as the divine prerequisite of the incarnation. Cyril regularly repeats a variation of Philippians 2:6–8: the ‘only-begotten Word of God’ subsequently ‘emptied’ or ‘humbled’ himself in order to ‘become as we are’ or ‘take on our form’. The Son who shares the essence of the Father did not change into something other than what he had always been, nor did he descend upon or enter into an already existing human person. Rather, the eternal Logos of God became man, and that man is Jesus Christ. To put it another way, the pre-existing Son and the child born of Mary are one and the same person, fully divine and fully human. The Word condescended to our condition and became one of us.

The fourth strategy the Alexandrian bishop employs for the benefit of his flock is using mixture language to describe the manner in which the divine and human natures are unified in the incarnation. Cyril presses into service a variety of terms that share synonymous (though not always identical) meanings, ranging from ‘mixing/mingling’ to ‘interweaving’ to ‘combining’ two or more elements. His purpose is to find ways to stress the mysterious and inseparable unity of the divinity and humanity in Christ. The initial point of inquiry here is to consider what terms Cyril used and when he used them. It is noteworthy that mixture language appears in two letters before the Nestorian debate and two at its height, showing that the controversy did not deter him from this strategy, at least initially. In Festal Letter 8.6, written in 420, Cyril names Athanasius, his model of the pure orthodox faith, as one who declared Christ's incarnation a σύνοδος (‘conjunction’ or ‘coming together’) of two dissimilar realities, namely divinity and humanity, into the same space.³⁷ Cyril describes the ‘coming together’ of the divine and human as an ineffable ‘mixture’ (ἀνακράσɛως).³⁸ Later in the same letter, he describes the properties of humanity ‘mingling’ (κεκερασμένον) with the glories of God and identifies the Christ we worship as the ineffable ‘ἀναμίξας’ (‘mixture’) of the divine and human.³⁹ Similar language appears in letter 10, written for 422, where Cyril comments on Paul's identification of Jesus as the ‘mediator between God and man’. Christ's mediation is possible because of the ‘mixing together’ (κɛράσας) of an ‘ineffable combination’ (ἀῤῥήτῳ συνοδῳ) of the divine and human in his person.⁴⁰

Mixture language appears again in letter 17, written in 429. By this point, Cyril was embroiled in the controversy with Nestorius over the doctrine of the incarnation. In this letter, he continues to draw upon mixture language, but chooses different terms. Of the five words he uses in letter 17, he repeats none of the words for ‘mixing’, ‘mingling’ or ‘blending’ that he had used in letters 8 and 10 just under a decade earlier. In letter 17, Cyril maintains that Scripture teaches the ‘binding into unity’ (συνδοῦντɛς) our nature with the Word's, and ‘interweaving’ (ἀναπλέκοντɛς) both natures into one so that we worship the one Son of God who has become human.⁴¹ A little further on in the same letter, he again refers to the incarnation as an ‘interweaving’ or ‘combination’ of the divine and human, this time using the term συμπλοκήν.⁴² Two other terms he draws upon to describe the union of the Son with his humanity in this letter are συγκράσιν and ἀνακιρνὰς.⁴³ Both terms convey the sense of ‘mixing together’, ‘mingling’ or ‘uniting’.

The last two uses of mixture language in the Festal Letters occur in letters 18 and 20 written for the years 430 and 432, respectively. The dates of these letters bookend the Council of Ephesus which convened in 431. In letter 18, Cyril uses the illustration of a stream flowing from a river to demonstrate that the Son is of the same essence as the Father. But like water from a river that has been ‘mixed’ (μέμικται) with earth, so ‘“The Word became flesh” in the union of the economy’.⁴⁴ In letter 20, Cyril takes aim at his Nestorian opponents who separate the Word from the human being and ‘with difficulty assign to him [Christ] a simple conjunction (συνάφɛιαν)’.⁴⁵ Cyril himself never uses the word συνάφειαν in a positive manner to explain the incarnation. He only employs it to describe the position of his opponents. In fact, Cyril uses this word over 20 times in On the Unity of Christ, one of his latest and most theologically mature works, to describe the Nestorian model of the incarnation. Evidently, he did not believe the word adequately captured the notion of inseparable union as do the other terms he chooses. In fact, when we compare the mixture language of the Festal Letters with the terminology in On the Unity of Christ, we find him in the latter text no longer using mixture terms – except for συνάφɛιαν, which continued to function as a polemical term against Nestorius. Likewise, from 430 until the end of his life in 444, he dropped his earlier, positive use of mixture language from the Festal Letters. Given the way the Nestorian controversy evolved, such expressions became more harmful than helpful.⁴⁶ In his later years, he relied mostly on scriptural language and key theological convictions (as I will explain below), to describe the God-man. The table below lists the terms, letters and their dates where Cyril uses mixture language in the Festal Letters to denote the manner of union of the divinity and humanity in Christ.

The second point of inquiry regarding Cyril's use of mixture language is how these words function in his writings. Why did Cyril choose these particular terms and what was he trying to convey? First, it is important to note that mixture language had a history in the church's theological tradition before Cyril, notably in the writings of Gregory of Nazianzus and Gregory of Nyssa.⁴⁸ Aaron Riches observes that a number of pre-Chalcedonian fathers ‘of undoubtedly orthodox pedigree’ used the language of mixture or mingling to ‘account for the intimacy of union’ in Christ.⁴⁹ Of the figures of the fourth century, Beeley has argued persuasively of the Nazianzen's profound influence on Cyril's Christology, including his use of mixture terminology.⁵⁰ Though Cyril is following an established trajectory, he reaches for a plethora of terms to designate the manner of union between the divine and human natures in Christ, and, with the exception of συνόδω and ἀναπλέκοντες, he never uses them more than once in his Festal Letters. Are Cyril's word choices significant? Patrick Gray's observation that Cyril regularly uses ‘insouciant language’ throughout his writings is especially helpful here.⁵¹ That is, Cyril is not always aiming for exactitude in his vocabulary. The lack of precision that appears in some of Cyril's words, however, does not mean he was careless about the doctrines he was explaining or indifferent about whether or not his audience understood them. Rather, he chose common, familiar terms within conceptual reach of most Egyptian Christians of the time in order to bring home to them a very important truth: Jesus Christ is the Son of God made man, fully divine and fully human with both natures, however different, uniting in some way so that Christ is really one and not two separate entities. Unlike his Cappadocian counterparts, who may have employed mixture language with more philosophical nuance, Cyril does not seem to share that same concern. He cares more about effectiveness in communication than philosophical sophistication.⁵² Cyril knew his audience and must have believed that the terms he used had enough explanatory power to get his message across without being misleading, confusing or overly technical.⁵³

Further, because Cyril believed the incarnation was an ‘ineffable union’, we would expect him to reach for a variety of terms in his efforts to convey something beyond human comprehension. He was aware that human language, however theologically or philosophically sophisticated, cannot erase mystery. As Gray observes, Cyril's select vocabulary was ‘not to define…but to point to’ the reality of the Word becoming flesh.⁵⁴ If a divine act of God like the incarnation cannot be fully understood, human words will always fall short of providing a full and comprehensive explanation.⁵⁵ Though imperfect, the terms Cyril uses did what they were supposed to do: they provided some sense of how Christ is one person who is both divine and human without reducing the mystery.

Theological convictions informing Cyril's Christology

Cyril of Alexandria was adamant that Christians scattered throughout his Egyptian diocese understand that Christ is a single person who is both divine and human. He believes his teaching was consistent with Scripture and the theological tradition he inherited. He gives no quarter to any notion of dividing the divine Son from the human Jesus. But what, specifically, did Cyril believe was at stake? Why did he so vociferously insist on a unitive Christology? Throughout the Festal Letters, two primary doctrinal principles come to the fore that undergird Cyril's thought that help answer these questions. First, Cyril held a strong view of divine immutability. He rejected any model of the incarnation that suggested change or alteration in the divine nature, as seen in his consistent denial of any attempts to portray the incarnation as the Word transmuting into flesh. Likewise, he rejected any notion that the divine nature was diluted due to its union with human nature. In either case, Jesus Christ would not be fully God. Such a diminished Jesus would be incapable of divine action and unworthy of worship. Rather, the Word was, is and always will be God even after assuming human flesh. Cyril stresses this theological conviction with great frequency throughout the Festal Letters.⁵⁶ From his very first letter, he insists that in the incarnation the Son remains the same, ‘preserving his deity without change or alteration on account of the Incarnation, but being the very one who was and will be always’.⁵⁷ This conviction remained with Cyril throughout his episcopal career.

Second, Cyril stresses the unity of Christ, because dividing Christ into two separate entities would shatter the gospel message of redemption. Salvation requires an undivided Son and Lord in the incarnation. Thus, Cyril's unitive Christology is inseparably bound up with his soteriology. The theme of what some have called the ‘divine exchange’ is everywhere in these letters (i.e. the teaching that the Son took what belonged to us that he might give us what belongs to him). Athanasius's well-known dictum, ‘He [the Word] became man that we might become divine’ captures Cyril's sentiment.⁵⁸ Only God can save, and only humanity needed saving. Thus, God became man. By sharing our nature, undergoing our death and rising victoriously from the grave, the blessings of salvation Christ dispenses to humanity are manifold: he brings our nature back to its ancient incorruption,⁵⁹ joins us to heavenly realities,⁶⁰ makes us citizens of heaven,⁶¹ puts to death the pleasures in our flesh and restores us to virtue,⁶² makes us stable and sensible,⁶³ refashions us by the Spirit into his likeness,⁶⁴ strengthens our nature and gives us power over sin,⁶⁵ impresses his glory upon us,⁶⁶ restores us to life,⁶⁷ transforms us into a purity worthy of God,⁶⁸ fills us with heavenly goods⁶⁹ and enriches us with new birth by the Spirit.⁷⁰ Cyril exclaims:

In short, what is ours has become his in the economic appropriation, in order that we too, in what is peculiarly his, might ascend with him and through him, gaining that thing by the kindness that is from his. He said accordingly, ‘I am going to my Father and your Father, and my God and your God.’ For we have been named sons of God, having the Only-Begotten as firstborn and brother in the flesh.⁷¹

This is the reason that Jesus Christ must not be separated into two beings, persons or centres of consciousness, one divine and one human. According to Cyril, a divided Christ cannot save. Salvation is only possible if Christ is the very person of the Son who became exactly what we are, sin excepted, while maintaining what he had always been. Only through this unity of natures in the one person of Christ can human nature be redeemed and renewed.

Conclusion

Cyril's Festal Letters portray a bishop who cared a great deal about the way those under his care thought and spoke about Christ. Though he stresses that the mystery of God becoming man is great indeed, he looks to Scripture, especially John 1:14 and Philippians 2:6–8, to provide the framework and guiding language to confess the church's central doctrine that the divine Son lowered himself to our condition and ‘became’ what we are. He also draws upon terms common in his day and already used by some of his theological predecessors to help explain that the divine and human are inseparably united in Christ Jesus. Cyril's twin theological convictions that God is immutable and that only the Son incarnate can save us further undergird his unitive Christology. Throughout his letters, there is a remarkable degree of consistency in Cyril's use of Scripture and core principles concerning the incarnation. Though he eventually left mixture language to the side and made other adjustments in terminology over the course of the Nestorian controversy,⁷² Cyril of Alexandria believed that Jesus Christ is the one Son of God who existed without flesh before the incarnation and now exists with flesh after the incarnation without any division or change.