Definition

Christology is the locus of systematic theology that treats the person and work of the Lord Jesus Christ: who he is in himself, and what he has accomplished for the salvation of his people. The word derives from the Greek Christos (“Anointed One,” the Messiah) joined to logos (“word,” “doctrine”). As a discipline, Christology asks and answers two coordinate questions that the Scriptures themselves pose: “What do you think about the Christ? Whose son is he?” (cf. Matthew 22:42), and “Why did the Christ come?” The first question concerns his person; the second concerns his work. The Reformed tradition has insisted that these two may be distinguished but never separated, for it is precisely who Christ is — true God and true man in one person — that qualifies him to do what he does as the one Mediator between God and men.

Classically, Christology unfolds along several axes. Concerning the person of Christ, it treats the incarnation, the hypostatic union, the two natures (divine and human), and the communicatio idiomatum (the communication of properties). Concerning the work of Christ, it treats his threefold office (the munus triplex) of prophet, priest, and king, and his two estates of humiliation and exaltation, culminating in the great theme of the atonement. This overview surveys the whole terrain; the companion guides develop the person, the offices, and the atonement in detail.

Why It Matters

Christology is not one doctrine among many; it is the hinge upon which the whole of Christian faith turns. The eternal life that the gospel promises consists in knowing the Father and the one whom he has sent (cf. John 17:3). To err concerning Christ is therefore not to misjudge a peripheral matter but to forfeit the saving knowledge of God. The ancient church understood this when it confessed that “the salvation of the soul” was at stake in every word of the Definition of Chalcedon. A Christ who is less than fully God cannot save, for no creature can bear the infinite weight of divine wrath or reconcile us to the infinite God. A Christ who is less than fully man cannot save us, for what he has not assumed he has not healed. A Christ in whom the two natures are confused or divided is no Mediator at all.

For the believer, Christology is intensely practical and doxological. Our assurance of pardon rests on the dignity of the One who bore our sins; our hope of resurrection rests on the One who rose; our access to the Father rests on the One who ever lives to intercede. To meditate on the person and work of Christ is to be drawn into worship, for “in him the whole fullness of deity dwells bodily” (Colossians 2:9). The aim of all Christology is finally adoration: that every knee should bow at the name of Jesus and every tongue confess that he is Lord, to the glory of God the Father.

Map of the Locus

The territory of Christology may be charted under the two great headings of person and work, with several sub-doctrines under each.

The Person of Christ

This branch treats the constitution of the Mediator. It confesses the eternal deity of the Son, the second person of the Trinity, “begotten, not made, of one substance with the Father.” It treats the incarnation, whereby the eternal Word “became flesh and dwelt among us” (John 1:14), taking to himself a true human nature, body and reasonable soul, in the womb of the virgin Mary by the power of the Holy Spirit. It defines the hypostatic union: that the divine and human natures are united in the one divine person of the Son, “without confusion, without change, without division, without separation” (Chalcedon). It expounds the two natures, each retaining its own properties; the deity neither converted into flesh nor the humanity absorbed into Godhead. And it considers the communicatio idiomatum, the proper way of speaking whereby the attributes of either nature may be predicated of the one person. The companion guide The Person of Christ develops this branch fully.

The States of Christ

This sub-doctrine traces the Mediator’s career through two estates. The state of humiliation comprises his conception and birth in a low condition, his life under the law, the miseries of this life, the wrath of God, the cursed death of the cross, his burial, and his continuing under the power of death for a time. The state of exaltation comprises his resurrection on the third day, his ascension into heaven, his session at the right hand of the Father, and his coming again to judge the world. These two estates structure the entire narrative of redemption accomplished.

The Offices of Christ

The munus triplex answers how Christ executes his mediatorial work. As prophet, he reveals to us, by his Word and Spirit, the whole will of God for our salvation. As priest, he offers himself once for all a sacrifice to satisfy divine justice and reconcile us to God, and makes continual intercession for us. As king, he subdues us to himself, rules and defends us, and restrains and conquers all his and our enemies. The companion guide The Offices of Christ develops this branch, together with the two states.

The Atonement

The crown of Christ’s priestly work is the atonement: the sacrificial death by which he satisfied the justice of God, bore the penalty due to sin, and purchased the redemption of his people. Here the Reformed tradition confesses penal substitution and definite (particular) redemption — that Christ died not merely to make salvation possible but actually to secure the salvation of those given to him by the Father. The companion guide The Atonement develops the nature, design, and extent of this saving work.

Historical Development

The church’s confession of Christ was hammered out on the anvil of controversy in the first five centuries. Against the Ebionites, who denied Christ’s deity, and against Docetism, which denied the reality of his flesh, the apostolic and post-apostolic church affirmed both. The great crisis came with Arius (early fourth century), who taught that the Son was a creature, the highest of creatures but not truly God (“there was when he was not”). The Council of Nicaea (325) answered with the word homoousios — the Son is “of one substance with the Father” — and the Council of Constantinople (381) confirmed this against lingering Arianism.

Once the deity of the Son was secured, attention turned to how deity and humanity coexist in him. Apollinaris taught that the divine Logos replaced the human rational soul, leaving Christ less than fully man; he was condemned in 381. Nestorius so divided the natures as to imperil the unity of the person, hesitating to call Mary Theotokos (“God-bearer”); the Council of Ephesus (431) answered him. Eutyches erred in the opposite direction, so mingling the natures that the humanity was swallowed up “like a drop of wine in the sea.” Against all these, the Council of Chalcedon (451) issued its enduring Definition: one person in two natures, “without confusion, without change, without division, without separation.” This four-fold negation remains the boundary stone of orthodox Christology.

The medieval church refined the doctrine of the communicatio idiomatum and developed the satisfaction theory of the atonement, especially through Anselm’s Cur Deus Homo. The Reformation did not overturn the catholic Christology of the ecumenical councils but received and confirmed it, while recovering with fresh clarity the doctrines of justification and definite atonement. The Reformed orthodox, over against Lutheran teaching on the ubiquity of Christ’s body, articulated what became known as the extra Calvinisticum — that the Son, even in the incarnation, was not confined to the flesh but continued to fill and sustain all things.

The Reformed & Confessional Position

The Westminster Standards present a mature and balanced Christology, drawing together the catholic creeds and the Reformed emphasis on the covenant of grace. The Confession opens its treatment with the eternal appointment of the Son as Mediator:

“It pleased God, in his eternal purpose, to choose and ordain the Lord Jesus, his only begotten Son, to be the Mediator between God and man, the Prophet, Priest, and King, the Head and Saviour of his Church, the Heir of all things, and Judge of the world.” (WCF 8.1)

On the person, the Confession confesses the hypostatic union in Chalcedonian terms:

“The Son of God, the second person in the Trinity, being very and eternal God, of one substance and equal with the Father, did, when the fullness of time was come, take upon him man’s nature, with all the essential properties, and common infirmities thereof, yet without sin… So that two whole, perfect, and distinct natures, the Godhead and the manhood, were inseparably joined together in one person, without conversion, composition, or confusion. Which person is very God, and very man, yet one Christ, the only Mediator between God and man.” (WCF 8.2)

On the work, the Larger Catechism unfolds both the offices and the states. It answers that Christ executes the office of a mediator in his threefold capacity:

“Christ executeth the office of a prophet, in his revealing to the church, in all ages, by his Spirit and word, in divers ways of administration, the whole will of God, in all things concerning their edification and salvation.” (WLC 43)

The Shorter Catechism summarizes the offices in three memorable answers (WSC 24-26) and the states in two (WSC 27-28), confessing that Christ’s humiliation consisted in his being born in a low condition, made under the law, undergoing the miseries of this life, the wrath of God, and the cursed death of the cross, while his exaltation consists in his rising again, ascending, sitting at God’s right hand, and coming to judge the world. Throughout, the Standards keep person and work, accomplishment and application, inseparably bound to the covenant of grace, of which Christ is both Mediator and substance.

Contrasting Views

The errors that the church has rejected fall into discernible patterns, and they recur in every age under new names.

Concerning the person, Arianism denies the full deity of the Son, reducing him to a creature; its modern heirs include groups that deny the Trinity outright. Apollinarianism truncates Christ’s humanity by denying him a human soul or mind. Nestorianism so distinguishes the natures that it threatens to make two persons or two sons. Eutychianism (monophysitism) so confuses the natures that Christ becomes a third thing, neither truly God nor truly man. The Reformed answer, with Chalcedon, is to confess one person in two unconfused, undivided natures.

Concerning the work, especially the atonement, several non-Reformed theories diverge. The Arminian or universal-atonement view holds that Christ died for all without exception, securing salvation for none in particular but making all savable on condition of faith. The governmental theory (Grotius) holds that the cross was not a strict satisfaction of justice but a public demonstration of God’s displeasure with sin, upholding the moral government of the universe. The moral-influence theory (Abelard, and modern liberalism) holds that the cross saves merely by displaying God’s love and thereby moving sinners to repentance, denying any objective propitiation. Each of these, in its own way, weakens the substitutionary and penal character of the cross and severs the design of the atonement from its accomplishment. The Reformed position holds that Christ actually bore the penalty of his people’s sin, satisfied divine justice, and infallibly secured their redemption.

Connections to Other Loci

Christology stands at the center of the dogmatic web and touches every other locus. It presupposes the doctrine of God (Theology Proper) and especially the Trinity, for the incarnate One is the eternal second person. It rests upon the decrees of God, for the Son was “fore-ordained before the foundation of the world” (cf. 1 Peter 1:20) in the covenant of redemption. It fulfills anthropology, for Christ is the last Adam who succeeds where the first Adam fell, the true image of God. It grounds soteriology entirely, for there is no benefit of redemption that does not flow from union with Christ. It supplies the foundation of ecclesiology, since the church is his body and bride. And it shapes eschatology, for the returning King will raise the dead and judge the world. Every road in theology runs through Bethlehem, Calvary, and the empty tomb.

Christ & the Gospel at the Center

In Christology the gospel is not merely discussed; it is embodied, for Christology is the gospel rendered in doctrine. The good news is precisely that the eternal Son took our flesh, lived our life under the law, died our death under the curse, and rose for our justification. Every dogmatic distinction here serves a saving purpose. The two natures are not a metaphysical puzzle but the very ground of our salvation: the human nature so that one of our race might obey and suffer in our place; the divine nature so that his obedience and suffering might be of infinite value and avail for a multitude no man can number. The hypostatic union means that when this man bled, God’s own Son bled; and so the church purchased “with his own blood” (cf. Acts 20:28) is purchased at infinite cost. To study Christ rightly is to be brought again and again to the foot of the cross and the threshold of the empty tomb, and there to worship.

Pastoral & Practical Significance

Because the believer’s whole salvation hangs on the person and work of Christ, Christology is the deepest wellspring of pastoral comfort. When conscience accuses and Satan presses, the saint flees not to his own righteousness but to the One who is “our wisdom and our righteousness and our sanctification and our redemption” (cf. 1 Corinthians 1:30). The dignity of the Mediator assures the troubled soul that no sin is too great for his blood, and the perfection of his obedience assures us that we stand accepted in him. His ongoing priestly intercession means that the weakest believer never stands before God unrepresented. His kingly rule means that no enemy, no affliction, and no power of death can finally prevail against those he has redeemed. And his prophetic office means that we are not left to grope in darkness but have in him the full and final revelation of the Father. To know Christ truly is to find rest for the soul and to be drawn upward in love and obedience to the One who first loved us.

Key Terms

• Christology — the doctrine of the person and work of Christ.
• Hypostatic union — the union of the divine and human natures in the one person (hypostasis) of the Son.
• Incarnation — the act by which the eternal Word took to himself a true human nature.
• Communicatio idiomatum — the communication of properties; the predicating of the attributes of either nature to the one person.
• Munus triplex — the threefold office of Christ as prophet, priest, and king.
• States (estates) of Christ — the two conditions of humiliation and exaltation.
• Theotokos — “God-bearer,” the title affirming that the one Mary bore is God the Son.
• Extra Calvinisticum — the Reformed teaching that the Son, even incarnate, continues to fill and sustain all things beyond the flesh.

Key Scripture References

• John 1:1, 14 — the eternal Word, who was God, became flesh.
• Philippians 2:5-11 — the humiliation and exaltation of Christ.
• Colossians 1:15-20 — Christ as image of God, Creator, and Reconciler.
• Colossians 2:9 — the fullness of deity dwelling bodily.
• Hebrews 1:1-3 — the Son as final revelation, upholding all things.
• Hebrews 2:14-18 — Christ partaking of flesh and blood to be a merciful high priest.
• 1 Timothy 2:5 — one Mediator between God and men, the man Christ Jesus.
• Acts 20:28 — the church purchased with God’s own blood.

Further Study

• Westminster Confession of Faith, chapter 8; Larger Catechism Q. 36-57; Shorter Catechism Q. 21-28.
• The Definition of Chalcedon (451) and the Nicene-Constantinopolitan Creed.
• Companion guides: The Person of Christ, The Offices of Christ, The Atonement.
• John Calvin, Institutes of the Christian Religion, Book II, chapters 12-17.
• Anselm, Cur Deus Homo.