What is the hypostatic union?
Question 3005
The hypostatic union is one of the most profound doctrines in all of Christian theology. It describes how Jesus Christ can be both fully God and fully man at the same time, united in one Person. This is not merely an academic curiosity for theologians to debate; it is essential to the Gospel itself. If Jesus is not truly God, He cannot save us. If Jesus is not truly man, He cannot represent us. The hypostatic union explains how both truths can be held together without contradiction.
Understanding the Term
The word “hypostatic” comes from the Greek ὑπόστασις (hypostasis), meaning “substance” or “person.” The hypostatic union refers to the union of two natures, divine and human, in one Person (hypostasis). This doctrine was formally defined at the Council of Chalcedon in AD 451, though it simply articulated what Scripture had always taught and the Church had always believed.
The Chalcedonian Definition stated that Jesus Christ is “acknowledged in two natures, without confusion, without change, without division, without separation; the distinction of natures being by no means taken away by the union, but rather the property of each nature being preserved, and concurring in one Person and one Subsistence, not parted or divided into two persons, but one and the same Son, and only begotten God, the Word, the Lord Jesus Christ.”
Let’s break this down into language we can grasp.
Two Complete Natures
Jesus possesses two complete natures: one divine and one human. His divine nature includes all the attributes of God: eternality, omniscience, omnipotence, omnipresence, holiness, and every other divine perfection. His human nature includes everything essential to being human: a human body, a human soul, a human mind, human emotions, and human will. Neither nature is diminished or incomplete.
This is important because some heresies throughout history have denied or diminished one nature or the other. The Docetists claimed Jesus only appeared to be human but was really pure spirit. The Arians claimed Jesus was a created being, not truly God. The Apollinarians claimed Jesus had a human body but not a human mind or soul. The Eutychians claimed the two natures blended together into a third, mixed nature. All of these are errors. Jesus is fully and completely God. Jesus is fully and completely man. Both natures remain distinct and complete.
Without Confusion or Change
When the divine and human natures united in the Person of Jesus, they did not mix together or change into something else. The divine nature did not become human, nor did the human nature become divine. Oil and water may be placed in the same container, but they remain distinct. In a similar way (though all analogies fall short), the two natures of Christ remain distinct while being united in one Person.
This means that when we see Jesus hungry, tired, or suffering, we are seeing His human nature in operation. His divine nature cannot hunger or tire or suffer. Yet it is the same Person who is both omnipotent God and weary traveller. When Jesus says “The Father is greater than I” (John 14:28), He speaks from the perspective of His human nature in its state of humiliation. When He says “I and the Father are one” (John 10:30), He speaks of His divine nature’s essential unity with the Father.
Without Division or Separation
Although the two natures are distinct, they are not separable. Jesus is not two persons but one Person. He does not switch between being God and being man. Every act of Jesus is the act of the one Person, the God-man. When Jesus died on the cross, it was the Person of Jesus who died, though His divine nature did not and cannot die. When Jesus is worshipped, both natures are present in the one Person who receives that worship.
The theologians speak of the “communication of attributes” (communicatio idiomatum). This means that what can be said of either nature can be said of the Person. Because Jesus is God, we can say “God died on the cross” (Acts 20:28, speaking of “the church of God, which he obtained with his own blood”). Because Jesus is man, we can say “the man Christ Jesus” is in heaven (1 Timothy 2:5). The Person of Christ, who is both God and man, can be described according to either nature.
Why the Hypostatic Union Matters
This doctrine is not abstract speculation; it is essential to the Gospel. Consider why:
Jesus must be God to save us. Only God has the power to defeat sin, death, and Satan. Only an infinite God can offer a sacrifice of infinite value. If Jesus were merely a man, even the best of men, His death could not atone for the sins of the world. “There is salvation in no one else” (Acts 4:12) precisely because no one else is the God-man.
Jesus must be man to represent us. The book of Hebrews emphasises this. “Since therefore the children share in flesh and blood, he himself likewise partook of the same things, that through death he might destroy the one who has the power of death” (Hebrews 2:14). “For we do not have a high priest who is unable to sympathise with our weaknesses, but one who in every respect has been tempted as we are, yet without sin” (Hebrews 4:15). Jesus had to become what we are in order to save us. He took on human nature so that He could stand in our place, bear our sins, and reconcile us to God.
Jesus must be both God and man to be our Mediator. “For there is one God, and there is one mediator between God and men, the man Christ Jesus” (1 Timothy 2:5). A mediator must have standing with both parties. Jesus, being both God and man, can lay His hand on both God and humanity. He bridges the infinite gap that sin created.
The Incarnation Continues
When the eternal Son took on human nature, it was not temporary. The incarnation was a permanent union. The risen and glorified Jesus remains the God-man. He ascended bodily into heaven. He sits at the right hand of the Father in His glorified human body. He will return in that same body (Acts 1:11). For all eternity, the second Person of the Trinity will be united with human nature. This is the measure of God’s commitment to our salvation and His identification with us.
Conclusion
The hypostatic union describes the most extraordinary event in history: the eternal God taking on human nature without ceasing to be God. In Jesus Christ, two complete natures, divine and human, are united in one Person, without confusion, without change, without division, without separation. This union makes possible our salvation, for only the God-man could be both the infinite sacrifice for sin and our representative and substitute before the Father. Far from being abstract theology, the hypostatic union is the foundation of the Gospel and the ground of our hope.
“For in him the whole fullness of deity dwells bodily.” Colossians 2:9
Bibliography
- Grudem, Wayne. Systematic Theology. Zondervan, 1994.
- Macleod, Donald. The Person of Christ. Contours of Christian Theology. IVP, 1998.
- Wellum, Stephen J. God the Son Incarnate: The Doctrine of Christ. Foundations of Evangelical Theology. Crossway, 2016.
