The Communicatio Idiomatum: Preserving the Unity of Christ and the Integrity of His Natures

Introduction

The communicatio idiomatum, or the communication of properties, is a vital doctrine of Christology that safeguards the unity of Christ’s person while affirming the integrity of His two natures. It reflects a theological method rooted in Chalcedonian Christology and the Reformed tradition, both of which confess that Christ’s natures are without change, confusion, separation, and division. This paper will approach this doctrine from a Trinitarian, Chalcedonian, and Reformed framework, defining it in light of its biblical and historical interpretation, defending it against historical and contemporary distortions, and declaring it essential to proper Christology and the Christian Faith. The communicatio idiomatum, grounded in the hypostatic union and expressed in Scripture, rightly attributes divine and human qualities, properties, and characteristics to the one Person of Christ, thereby preserving orthodox Christianity and sustaining the Church’s worship, preaching, and eschatological hope.

Define

The communicatio idiomatum asserts that what applies to Jesus’ humanity or divinity can be stated to his whole person, emphasizing the unity of his person and the ‘communication of attributes’ between his two natures. This realization by the Chalcedonian Fathers builds upon the hypostatic union. Christ exists with both a divine nature and a human nature united in his person or hypostasis: “This hypostasis has divine nature (it is ‘consubstantial with the Father’), and gains human nature in time (it is ‘consubstantial with us… in the last days’). Since what is involved is a union of two natures in one hypostasis, this union of natures is usually labelled the ‘hypostatic union.’”¹ This term, ‘the hypostatic union,’ helps clarify Christ’s ontology in the Incarnation. Still, it does not explicitly explain how the two natures relate to each other, aside from being united in the one person of Jesus. Tracing its development throughout history helps one to understand the communicatio idiomatum in light of the hypostatic union. However, it is necessary first to define the doctrine by examples from Scripture, the Christian’s sole infallible and inerrant authority, far more superior and valuable than anything church tradition and history could provide.

In Acts 20:28, Paul addresses the Ephesian elders, saying, “Pay careful attention to yourselves and to all the flock, in which the Holy Spirit has made you overseers, to care for the church of God, which he obtained with his own blood.”² In short, Paul calls the blood of Christ the blood of God Himself, for he writes the elders “to care for the church of God,” and then says “which he obtained with his own blood.” Furthermore, in 1 Corinthians, Paul writes, “None of the rulers of this age understood this, for if they had, they would not have crucified the Lord of glory” (1 Cor 2:8). Fundamentally and perspicuously, both instances properly attribute divinity to the Son so that Christians can say, “God bled,” “God was crucified,” or even “God died.”

Historical Development

The development of the communicatio idiomatum is inseparable from the early church’s defense of Christological necessities. Therefore, though this essay is not of the historical theology type, defining the systematic doctrine is nearly impossible apart from elaborations of it in history. While the term may not have occurred in early conciliar responses and decisions, it was expressed and articulated through their Scriptural belief that Christ possesses two natures united in one person.

The First Council of Nicaea (325 AD), in response to Arianism or the belief that the Son is a created being inferior to the Father, declared that the Son is “homoousios” or “of the same substance” as the Father, establishing Jesus’ divinity and eternality as orthodox doctrines.³ Furthermore, the Nicene Creed elaborates that the Son of God became man, yet this is not quite yet a clarification of his human nature. The First Council of Constantinople (381 AD), in response to Apollinarianism or the belief that Christ’s human person was indwelled with the divine mind and soul of the Logos so that his human nature was incomplete, established Christ’s full humanity as a Scriptural doctrine.⁴ These two earliest ecumenical councils led to the development of the Nicaeno-Constantinopolitan Creed, an exposition of Christology and the Trinity, yet there were many Christological errors and essentials yet to be realized.⁵

Following the first two ecumenical councils, there were several Christological debates. Primarily, the discussion consisted of two schools. The Alexandrines emphasized the unity of Christ’s person, while the Antiochenes emphasized the distinction in his natures.⁶ Both schools also had their errors and risks, however. On the one hand, the Alexandrines, by emphasizing Christ’s person, risked confusing or changing his natures, such as the case of Apollinarianism. On the other hand, the Antiochenes risked dividing or separating Christ into two persons by emphasizing his two natures. The latter is precisely what happened in Nestorianism, addressed at the Council of Ephesus (431 AD). This particular council was called to respond to Nestorius, who preferred the term “Christotokos” or “Christ-Bearer” over “theotokos” or “God-Bearer” when referring to Mary, Jesus’ mother, and effectively divided Christ into two persons.⁷

The Council of Chalcedon (451 AD) further refuted this position and error. Chalcedon sought to remedy the divide between the Alexandrines and the Antiochenes and their respective heretical interpretations, Eutychianism or Monophysitism (a single nature) and Nestorianism. It produced the Definition of Chalcedon, safeguarding orthodox Christology from four errors—change, confusion, separation, and division—with the former two responding to Eutychianism and the latter two responding to Nestorianism.⁸ The result of the Council and its Definition was the official ratification of the hypostatic union, and therefore, the communicatio idiomatum, although still not in name.

What followed the Council of Chalcedon were the Second and Third Councils of Constantinople (553 AD, 681 AD), both of which contributed to orthodox Christology and further clarified and reiterated the hypostatic union.⁹ However, after these two councils, the church, as a whole, did not elaborate on Christology for quite a long time as it had been mostly settled. However, John of Damascus (c. 675–c. 749), “whose work de fide orthodoxa (“On the Orthodox Faith”) is of considerable importance in the consolidation of a distinctively Eastern Christian Theology,”¹⁰ wrote of the communicatio idiomatum, demonstrating the Christological continuity between the East and the West at this point:

Moreover, the Word appropriates what is human (for what belongs to his holy flesh is his) and communicates his own attributes to the flesh by the method of exchange on account of the parts coinhering in each other and the hypostatic union, and because he was one and the same who “performs what is proper to both the divine and the human in each form in communion with the other.”¹¹

Furthermore, he writes the following, further explaining the communicatio idiomatum in light of the hypostatic union:

Therefore, when we are speaking of the divinity, we do not attribute to it the properties of the humanity (for we do not say that divinity is passible or created), nor do we attribute to the flesh, that is to say, to the humanity, the properties of the divinity (for we do not say that flesh, that is to say, humanity, is uncreated). But in the case of the hypostasis, whether we are speaking of it in terms of the combination, or whether we are speaking of it in terms of one of its parts, we attribute the properties of both natures to it.¹²

In short, what is true of one nature is either spoken of in light of its nature or the hypostases, and since the hypostasis is unified in two natures, the other nature in which the attribute is not derived can be predicated to the attribute. For example, following this logic, one can say, “Man is man, Christ is man, and God is man. The attribute in question is manness. It is quite easy to attribute manness to man. Christ has a human nature, so manness also applies to him, but Christ also has a divine nature, so it is proper to attribute manness to God since, in person, Christ is God. However, the nuance is that manness cannot be ascribed to the divine nature alone, only to the human nature and to Christ, who is God.

Furthermore, in the High Medieval Era, Christology and the communicatio idiomatum, this time by name, were addressed by scholastics, such as Peter Lombard and Thomas Aquinas.¹³ Aquinas and, later, Lutheran reformers such as Martin Luther and Philip Melanchthon provide the “manness” example of communicatio idiomatum succinctly: “God is man and man is God.”¹⁴

Defend

This section of the essay will first address the heretical positions included in the historical narrative subsection—Arianism, Apollinarianism, Nestorianism, Eutychianism (monophysitism), and monothelitism—and explain why their position is incompatible with the doctrine. Then, it will discuss the debate between the Lutheran and Reformed Traditions on the three kinds or genera of the communicatio idiomatum—genus idiomatum, genus apotelesmaticum, and genus majestaticum, or auchematicum.¹⁵

Arianism, Apollinarianism, Eutychianism, and Monothelitism

Fundamentally, the heresies of the Early Church either prevented or abused the communication of properties. In Arianism and Apollinarianism, there is a complete prevention. For the former, if Christ is not divine, then a communication of attributes is impossible, for the divine attributes cannot be predicated to his person. Likewise, in Apollinarianism, if Christ does not have a human mind and soul, then salvation is incomplete: “Whoever has set his hope on a human being without a mind is actually mindless himself and unworthy of being saved in entirety. The unassumed is the unhealed, but what is united with God is also being saved.”¹⁶ Not only does Apollinarianism make salvation impossible, but, by logic, it also makes the communicatio impossible, for if there is a denial of either nature, there can be no communication.

Likewise, monothelitism, the heresy addressed at the Third Council of Constantinople in which Christ has an active divine will and a passive human will, is a deplorable position in which the humanity of Christ is diminished.¹⁷ Therefore, reappropriating Gregory of Nazianzus, “Whoever has set his hope on a human being without a [passive human will]… [is] unworthy of being saved in entirety. The [passive will] is the unhealed,”¹⁸ for no human being has a passive will. The communicatio, in this situation, is impossible for the confines of it, the hypostatic union, is corrupted.

The same can be said for Eutychianism or monophysitism. Because there is a single nature in Christ—the divine nature has absorbed the human nature—the communication of properties is blurred into confusion and incoherence. Furthermore, the Chalcedonian Definition condemns confusion and change, or the absorption of one nature into the other, demonstrating the position’s incompatibility with the hypostatic union and the communicatio idiomatum.¹⁹

Nestorianism

Nestorianism is the true antithetical position to the hypostatic union and the communicatio idiomatum. By the time this heresy was introduced through radical Antiochene Christology, “the following propositions had gained widespread acceptance within the church: 1. Jesus is fully human 2. Jesus is fully divine. If both of these statements were true, it was argued, then what was true of the humanity of Jesus must also be true of his divinity - and vice versa.”²⁰ Two examples of this are the following: “Jesus Christ is God; Mary gave birth to Jesus; Therefore Mary is the “Mother of God” or the theotokos, and “Jesus suffered on the cross; Jesus is God; Therefore God suffered on the cross.”²¹ Since Nestorius refused to call Mary the theotokos and preferred the term Christotokos, he essentially divided the two natures of Christ into two persons—the divine Logos and the human Jesus. Refuting this position, Gregory of Nazianzus writes, “Whoever imports two ‘sons,’ one from God the Father, a second from the mother and not the one and the same Son, loses the adoption promised to those who believe aright. Two natures there are, God and man (since there are both soul and body), but not two ‘sons’ or two ‘Gods.’”²² If there is not a single person, the natures cannot be communicated through a unified person, only through their respective persons—the divine nature through the Logos and the human nature through the human son of Mary.

Lutheran vs. Reformed

The Formula of Concord (1577) provides the three genera of the communicatio idiomatum: genus idiomatum, genus apotelesmaticum, and genus majestaticum, or auchematicum. The first two genera are accepted by both Lutherans and the Reformed, but the third genus is central to the debate.²³

Genus Idiomaticum

The first of the genera is fundamentally the communicatio idiomatum in the way that this essay has discussed thus far: the communication of attributes derived from each nature and predicated to the person of Christ. A quote from John Calvin puts it well:

This is the way in which Scripture speaks about Jesus Christ. Sometimes it credits him with what can only apply to humanity, sometimes with what especially belongs to deity, sometimes with what relates to both natures combined rather than to one. Indeed it so carefully expresses the union of Christ’s two natures that it assigns to one what belongs to the other, a literary device called by the early Fathers a ‘transfer of properties.’²⁴

Because this essay has already discussed this ideology thoroughly, it need not be discussed further in this section. However, as the genus idiomaticum is the usual means by which the communicatio idiomatum is understood, it will be central to the rest of this essay.

Genus Apotelesmaticum

The second genus has “reference to the execution of the office of Christ: the communication of redeeming acts of the whole person to one of the two natures. Christ always operates in and through both. Thus, Christ, neither as God nor man alone, but as God-man, is [the] Mediator, Redeemer, King, High-Priest, Shepherd, etc.”²⁵ Both of his natures, divine and human, are unified in his singular person so that neither one is passive in all the works he does. Rather, the divine and human natures are active in all the works. For example, “He shed his blood according to his human nature, but the divine nature gave it infinite value” (1 Cor. 15:3; Gal. 1:4; 3:17; 1 John 3:8; Luke 9:56).²⁶ All that Jesus did after his incarnation was done as the God-Man, carrying out his saving work in the economy of salvation. Again, John Calvin explains it well:

For what we read there [in John’s Gospel] does not refer individually to his humanity and his deity, but to his whole person, inasmuch as he is God and man. Thus the Father has given him authority to forgive sins (John 1:29), to raise to life those he wills, to dispense righteousness, holiness and salvation. He was appointed Judge of the living and the dead, that he might be honoured like the Father John (5:21-23). He is the Light of the world, the good Shepherd, the only Door, the Vine John (9:5; 10:9, 11; 15:1). For he received these privileges when he was revealed in the flesh, though possessing them in his own right from before the creation of the world.²⁷

Calvin is not only speaking of the genus apotelesmaticum but also the pactum salutis, or covenant of redemption, and the enhypostasia of Christ’s human nature. Calvin says, “For he received these privileges when he was revealed in the flesh, though possessing them in his own right from before the creation of the world,” meaning that he possessed the privilege as Redeemer even before His incarnation and his human personality took this privilege and responsibility on as well. In other words, the divine Son took on human flesh, adding a human nature to himself so that he could redeem creation through his unified person.

Genus Majestaticum or Auchematicum

The third genus, the most debated of the three, posits that the characteristics, properties, and attributes of the divine nature are communicated to the assumed humanity of Christ so that Christ’s human nature is elevated, taking on both “operative attributes (omnipotence, omniscience, omnipresence) and the quiescent attributes (eternity, infinitude): all were communicated to Christ for inhabitation and possession, but only the operative for use.”²⁸ This communication of the divine attributes to human nature seems to undermine the Definition of Chalcedon—the natures are distinct, yet unified in the one person—and creates a human nature that is no longer human but divine, joined to the divine nature not by a unified person but by divine properties. Endorsement of the genus majestaticum is very dangerous if its logical conclusion is followed, as a blend of natures into a single nature is similar to Eutychianism. Rather, the correct way to understand the glorification of Christ’s humanity is not that it goes through change by adopting divine attributes but that it is joined to divinity by virtue of the Son of God in the incarnation. Rejection of the genus majestaticum preserves the distinctiveness of each nature while upholding the unity of Christ’s person.

Declare

The communicatio idiomatum, both in the case of the genus idiomatum and the genus apotelesmaticum, is essential for Christian life. It is necessary for soteriology, ecclesiology, and eschatology primarily because it is a direct, logical conclusion of the hypostatic union, as attested by Scripture and confessed by the historic church. Without it, Christology becomes fractured as the grounds for speaking of Christ’s natures and unified person becomes incoherent.

Soteriology

The communicatio idiomatum is necessary for salvation. Reformed Christians believe that salvation is monergistic, meaning God works and accomplishes it. The fact that Christians can say things such as “God was born for us,” “God suffered for us,” and “God died for us” is the axiomatic expression of this monergistic work. This exclamation is impossible without the hypostatic union and the communication of properties between the human and divine natures unified in Christ. This can be seen in On the Incarnation by Athanasius: “he who was made known and suffered in the body was not simply a human being but Son of God and Savior of all.”²⁹ Indeed, he was a human being, fully so, yet he was also the second person of the Trinity, the Son incarnate. Moreover, Athanasius writes, “with the common Savior dying for us, we, the faithful in Christ, no longer die by death as before according to the threat of the law, for such condemnation has ceased.”³⁰ In short, the Savior, who is fully man and fully God and suffers according to his humanity, no longer condemns those that believe in him (Rom. 8:1). Indeed, God himself who suffers does not condemn humanity because he has paid for the condemnation himself with his own blood.

Ecclesiology

Because it is so significant for soteriology, the communicatio idiomatum is also critical to the way the church worships. For instance, Lutherans argue for the ubiquity of Christ’s presence in the Eucharist, and this view is derived from the genus majestaticum.³¹ However, as previously demonstrated, not directly but through the means of refuting the genus majestaticum altogether, this view is irrational. One of the proper effects of the communicatio idiomatum in Reformed ecclesiology is the “Spiritual Presence” view of the Lord’s Supper. This view is described in the following way:

For the rest, if we direct our gaze and thoughts toward heaven, and are transported there to seek Christ in the glory of his kingdom (Col. 3:1), we will be separately fed by his flesh under the sign of the bread, and nourished by his blood under the sign of the wine, so as to enjoy him to the full. For although he withdrew his flesh from us and in his body ascended into heaven, he is nevertheless seated at the Father’s right hand and therefore rules with the Father’s power, majesty and glory. His kingdom is not so limited to any place or of such fixed dimensions that he cannot exhibit his power wherever he pleases, in heaven and on earth, or make known his presence with power and might or continually assist his own, living in them, sustaining them, strengthening them, invigorating them and serving them just as if he were physically present.³²

In this way, Reformed Christians, aware of the communicatio idiomatum, recognize that Christ’s body is localized in heaven, and they ascend to meet him there in heaven through the Lord’s Supper. Still, however, they recognize that according to his divinity, he is omnipresent and able to meet them anywhere, and this position—the localized human body and nature and the infinite divine nature as omnipresent—is known as the extra calvinisticum. Furthermore, this nuanced view of the Lord’s Supper demonstrates and is due to the distinctiveness and integrity of the two natures, all while recognizing that it is Christ, the Son of God, that they feast on in the Lord’s Supper.

Eschatology

Lastly, the communicatio idiomatum has profound implications for eschatology, primarily in the believers’ hope for resurrection, glorification, and the restoration of all things. In Romans 8, the Apostle Paul writes, “The Spirit himself bears witness with our spirit that we are children of God, and if children, then heirs—heirs of God and fellow heirs with Christ, provided we suffer with him in order that we may also be glorified with him. For I consider that the sufferings of this present time are not worth comparing with the glory that is to be revealed to us” (Rom. 8:16-18). Since the Son of God has joined humanity to himself, those who trust in his finished work are adopted by God and called Christ’s brothers. Furthermore, Paul provides the “golden chain of redemption” in Romans 8:30: “And those whom he predestined he also called, and those whom he called he also justified, and those whom he justified he also glorified.” Since the Son of God has been himself glorified, and since he joined humanity to himself, believers in him can be confident that they will also be resurrected and glorified, becoming like him according to the promise.

Conclusion

The communicatio idiomatum is essential to Orthodox Christology and Christian theology. It preserves the unity of Christ’s person and the integrity of his two natures. Built upon the Biblical witnesses and the hypostatic union, this doctrine guarantees that the properties and attributes of the divine and human natures are properly predicated on the one person of Christ. From the teachings of the Scripture to the ecumenical councils such as Chalcedon and through Reformation debates, the communicatio idiomatum has protected God’s church from error and heresy, although it has been a development throughout the history of the church. Far more than notional language, or the way in which Christians speak of the hypostatic union, the communicatio idiomatum is a reality of Christ’s ontology, and it undergirds the Gospel itself: God became man, lived the perfect life, suffered, died, was buried, rose from the dead, and ascended to heaven. Therefore, Christians would be wise to use Chalcedonian language when they speak of Jesus. Moreover, the fact that God himself has redeemed them should lead them to great joy, exultation, and worship, for they worship the God who became man.

Bibliography

Athanasius. On the Incarnation. Popular Patristics Series no. 44B, edited by John Behr. Crestwood, NY: St Vladimir’s Seminary Press, 2011.

Calvin, John. Institutes of the Christian Religion: Calvin’s Own Essentials Edition: A New Translation of the 1541 Institutes. Translated by Robert White. Edinburgh, UK: Banner of Truth, 2020.

Cross, Richard. The Communicatio Idiomatum: Reformation Christological Debates. Oxford, UK: Oxford University Press, 2019.

Gregory of Nazianzus. “Letter 101: The First Letter to Cledonius the Presbyter.” In On God and Christ: The Five Theological Orations and Two Letters to Cledonius. Popular Patristics Series no. 23, edited by John Behr. Crestwood, NY: St Vladimir’s Seminary Press, 2002.

Holcomb, Justin S. Know the Creeds and Councils. Grand Rapids, MI: Zondervan, 2014.

John of Damascus. On the Orthodox Faith. Popular Patristics Series no. 62, edited by John Behr. Crestwood, NY: St Vladimir’s Seminary Press, 2002.

McGrath, Alister E. Historical Theology: An Introduction to the History of Christian Thought. Malden, MA: Blackwell Publishing, 1998.

Schaff, Philip. The Creeds of Christendom. Vol. 1, The History of Creeds. Grand Rapids, MI: Baker Books, 1996.

Footnotes

1. Richard Cross, The Communicatio Idiomatum: Reformation Christological Debates (Oxford, UK: Oxford University Press, 2019), 2. ↩

2. Unless otherwise specified, all Scripture references are to the English Standard Version (Wheaton, IL: Crossway, 2016). ↩

3. Justin S. Holcomb, Know the Creeds and Councils (Grand Rapids, MI: Zondervan, 2014), 38–39. ↩

4. Alister E. McGrath, Historical Theology: An Introduction to the History of Christian Thought (Malden, MA: Blackwell Publishing, 1998), 52-52. ↩

5. Philip Schaff, The Creeds of Christendom, vol. 1, The History of Creeds (Grand Rapids, MI: Baker Books, 1996), 24–25. ↩

6. McGrath, 51–56. ↩

7. Ibid., 57–60. ↩

8. Schaff, 31. ↩

9. Holcomb, 78–82. ↩

10. McGrath, 124. ↩

11. John of Damascus, On the Orthodox Faith, Popular Patristics Series, edited by John Behr (Crestwood, NY: St Vladimir’s Seminary Press, 2002), ch. 47. ↩

12. John of Damascus, ch. 48. ↩

13. Schaff, 318. ↩

14. Cross, 20–21. ↩

15. Schaff, 319. ↩

16. Gregory of Nazianzus, “Letter 101: The First Letter to Cledonius the Presbyter,” in On God and Christ: The Five Theological Orations and Two Letters to Cledonius, Popular Patristics Series, ed. John Behr (Crestwood, NY: St Vladimir’s Seminary Press, 2002), 158. ↩

17. Holcomb, 80–81. ↩

18. Gregory of Nazianzus, 158. ↩

19. Holcomb, 57. ↩

20. McGrath, 59. ↩

21. Ibid. ↩

22. Gregory of Nazianzus, 157. ↩

23. Schaff, 319–321. ↩

24. John Calvin, Institutes of the Christian Religion, 242. ↩

25. Schaff, 319. ↩

26. Ibid. ↩

27. John Calvin, 243. ↩

28. Schaff, 320. ↩

29. Athanasius, On the Incarnation, 69. ↩

30. Ibid., 71. ↩

31. Schaff, 322. ↩

32. Calvin, 640–641. ↩