The hypostatic union, while arguably not at the forefront of most believers’ minds when it comes to matters of theology, is nevertheless a vitally important doctrine, especially regarding the study of the person and work of Christ known as Christology. While certainly on what can be considered the more “nerdy” side of the theological spectrum, the doctrine of Jesus being fully God and fully man, and how it relates to the message of salvation within Scripture, is a doctrine for which more believers should be familiar.
In this article, we will define the hypostatic union and take a brief look at the history of the doctrine, with the focus being why this doctrine is important for theology as a whole. Additionally, we will outline how the hypostatic union sheds light on the person and work of Jesus Christ, most notably his full divinity and full humanity and how both aspects reveal who Jesus is, what He has done on our behalf, and what He continues to do for us today.
Hypostatic Union Defined
The term hypostatic[i] is derived from the Greek word hypostasis meaning “personal”. Thus, the hypostatic union is the “personal union” or joining of the two natures of Jesus, namely His divine and human natures. Theologian Louis Berkhof helps shed some further light on the terms nature and person as they relate to the doctrine of the hypostatic union. He aptly comments the “term nature denotes the sum-total of all the essential qualities of a thing, that which makes it what it is…The term person denotes a complete substance endowed with reason, and, consequently, a responsible subject of its own actions.”[ii] To break that down a bit further, the nature of something includes the entirety of that something to include all its qualities or attributes. Since Jesus retained all of His divine attributes, His nature remained fully God. Moreover, the person of Jesus must include the reality that being fully human, He had the capability of reason and was responsible for His own actions.
While the specific phrase “hypostatic union” cannot directly be located in Scripture, the dual nature of Christ is nevertheless clearly evident. Furthermore, the hypostatic union is a doctrine widely accepted by the Church as accurately reflecting Jesus as both God (fully divine) and man (fully human). Douglas Kelly rightly notes the importance of this doctrine by stating, “In order to be the Mediator between God and mankind, so as to bring them back together, thereby saving lost humanity, Christ had to become man, while remaining at the same time God.”[iii]
History of the Doctrine
Council of Chalcedon
The Church had long affirmed the incarnation of Jesus, but the question remained as to how He could be fully God and fully man. Previous attempts by individuals such as Nestorius suggested Jesus existed as two different persons – Jesus as the man, and Jesus as God. This approach was rejected at the Council of Ephesus under the belief it created too much difficulty for Jesus to be treated as a human being. Another approach presented by Eutyches went the opposite direction with the emphasis placed on the union of the two natures of Jesus combining into one nature following the incarnation. Due to the obvious need to solidify a biblical stance on this important issue, over 500 bishops met at Chalcedon. Their goal was to develop a “coherent Christological position that walked the line between the Nestorian heresy (two persons in Christ) on the one hand and the Eutychean heresy (only one nature in Christ) on the other.”[iv]
What the Council of Chalcedon developed was founded upon earlier councils and creeds while further elaborating and identifying a needed distinction between the ideas of what comprises a person and the nature of something. It was determined Jesus had two natures in one person, both necessary for Him to be fully God and fully man. In relation to the Incarnation, the Council stated Jesus did not assume the human person; conversely, He assumed the human nature which was an important distinction. While the Council established was a helpful set of boundaries by which to better approach the reality of Jesus being both fully God and fully man without veering to the extremes of either Nestorianism or Eutychianism.
The essence of the Council’s position is found in the Chalcedon Creed, which in part declares Jesus should be “recognized in two natures, without confusion, without change, without division, without separation; the distinction of natures being in no way annulled by the union, but rather the characteristics of each nature being preserved and coming together to form one person and subsistence.”[v] The Council of Chalcedon helped center the focus back to the biblical truth of the divinity and humanity of Jesus, two issues we will now examine in relation to their biblical and practical importance for the believer.
Application and Importance of the Hypostatic Union
John 1:1 declares, “In the beginning was the Word, and the Word was with God, and the Word was God.” The Word refers to Jesus as the Logos, a term affirming His divinity. We also find the declaration that Jesus is fully God in Revelation 1:8 which states, “I am the Alpha and the Omega, the Beginning and the End,” says the Lord, “who is and who was and who is to come, the Almighty.” Thus, Jesus is clearly God from all eternity past and into eternity future. Being fully God, Jesus has all of the divine attributes attributed to God throughout Scripture. Theologian John Frame rightly notes, “Jesus, like God the Father and the Holy Spirit, is perfect love, righteousness, holiness, omniscient, omnipotent, eternal, immense, self-contained.”[vi] The Apostle Paul affirmed the deity of Jesus in Colossians 2:9 stating, “For in Him dwells all the fullness of the Godhead bodily.” There is no doubt within Scripture that Jesus is the Son of God and thus fully divine in His nature.
We also find in Scripture the full humanity of Jesus through the Incarnation. Passages such as Philippians 2:8 note, “And being found in appearance as a man, He humbled Himself and became obedient to the point of death, even the death of the cross.” This concept of Jesus being found in appearance is far more than Him merely looking like a man at first glance with the possibility of Him in actuality being something different than a man. The Greek word translated as appearance is schema which means “…the habitus, as comprising everything in a person which strikes the senses, the figure, bearing, discourse, actions, manner of life.” As noted earlier, this refers to His human nature and person, the sum total of who He was to include the capability of reason and responsibility for actions. The Incarnation then is the act of Jesus as God becoming human, God in the flesh.
Necessity of the Hypostatic Union
Now that we have established the theological validity of the hypostatic union, let’s take a moment to answer the needed “so what” aspect of the doctrine by taking a look at some elements of why Jesus being fully God and fully man is of the utmost importance. First, Jesus became flesh to be our Savior. Hebrews 2:14-15 states, “Inasmuch then as the children have partaken of flesh and blood, He Himself likewise shared in the same, that through death He might destroy him who had the power of death, that is, the devil, and release those who through fear of death were all their lifetime subject to bondage.” Perhaps one of the most well known passages in Scripture, John 3:16, also notes why Jesus came to earth in the flesh: “For God so loved the world that He gave His only begotten Son, that whoever believes in Him should not perish but have everlasting life.” Douglas Kelly rightly comments, “In taking on our flesh and giving himself to be our ransom, he shows us who God is, as the one who ‘spared not his own Son, but freely gave him up for us all’ (Rom. 8:32).”[vii]
Second, since Jesus is both fully God and fully man, he is uniquely qualified to be the mediator between God and Man. The Apostle Paul in 1 Timothy 2:5 states, “For there is one God and one Mediator between God and men, the Man Christ Jesus.” The role of a mediator is to guide both parties towards a resolution. When used in reference to Jesus as our Mediator, the resolution involves the restoration of relationship between God and man. Jesus came to mediate a New Covenant through His shed blood on the cross. Puritan theologian, William Ames, once noted, “It was necessary that Christ the Mediator should be God, and man: for unless he had been God, he could not be the spiritual King of our souls, dispensing life and death eternal: and unless he had been man he could not have been a head of the same kind with his body.”[viii] Without the hypostatic union of Jesus being fully God and fully man, He would not be able to execute His office of Mediator.
Third, Jesus serves as our great High Priest before God. Hebrews 2:17 outlines this priestly office stating, “Therefore, in all things He had to be made like His brethren, that He might be a merciful and faithful High Priest in things pertaining to God, to make propitiation for the sins of the people.” The Old Testament priests had to continually offer sacrifices to God with the high priest going once a year into the Holy of Holies to intercede before God on behalf of the people. Since the sacrifices were but a mere shadow of things to come, a perfect sacrifice was promised. As noted by John Frame, “Jesus as Priest offers the greatest sacrifice, his own body, and he now lives forever to make intercession for his redeemed people.”[ix] Being fully man, Jesus is able to sympathize with those He represents. Hebrews 4:15 states, “For we do not have a high priest who is unable to empathize with our weaknesses, but we have one who has been tempted in every way, just as we are–yet he did not sin.” As the Son of God, Jesus was sent by His Father to be the perfect sacrificial atonement for our sins and as a result, also appointed by God for that office. Thus He is uniquely qualified to be our Great High Priest before the throne of God.
Finally, the hypostatic union is important in order for Jesus to fulfill the prophecy of a King that would come through the line of David, the long promised Messianic King. As God, Jesus is King of kings and Lord of lords as noted in Revelation 19:16. Furthermore, as declared in Luke 1:33, His throne endures forever and His kingdom has no end. As King, all glory and honor are due His name. Moreover, Jesus being fully man fulfills the prophecies revealed in Scripture of Jesus as being from the “line of David”. Isaiah 9:7 promised “Of the increase of His government and peace there will be no end, upon the throne of David and over His kingdom, to order it and establish it with judgment and justice from that time forward, even forever. The zeal of the LORD of hosts will perform this.” Theologian John Owen reminds us that His “being clothed with our nature derogates (detracts) nothing from the true reason of divine worship due unto him, but adds an effectual motive unto it. He is, therefore, the immediate object of all duties of religion, internal and external; and in the dispensation of God towards us, none of them can be performed in a due manner without a respect unto him.”[x] In the hypostatic union, we see Jesus as eternal King, and as the King who will sit on the throne of David forever.
A Final Note…
The doctrine of the hypostatic union is far more than some dry and dusty theological term to be studied by theologians surrounded by a giant pile of scholarly works (although such people are prone to use the term). In reality, this doctrine is of great importance to the subject of Christology as a whole, and for believers to better grasp what Christ did on our behalf. To properly understand the person and work of Christ, as believers, we must appreciate Him as being both fully God and fully man. As both God and man, He alone is our Savior, Mediator, Priest, and King. It was necessary for Jesus to voluntarily come in the flesh to fulfill the will of His Father—that being the redemption and reconciliation of humanity to God through the cross. Unless Jesus was fully God and fully man, this act of redemption would have been incomplete. As both God and man, He came to earth, lived a sinless life, died on the cross, rose again, intercedes for us before God, and will one day return as the conquering King.
As we ponder the wonder and magnificence of this doctrine, may we be reminded of the words of John Owen who stated, “It is true, it is the person of Christ as God and man that is the proper and ultimate object of our love towards him; but a clear distinct consideration of his natures and their excellencies is effectual to stir up and draw forth our love towards him.”
This article first appeared in the Fall 2014 issue of Theology for Life on the person and work of Christ.
 John Owen, The Holy Spirit (Carlisle: Banner of Truth, 2009), 187-188.
[i] David Mathis, “What is the Hypostatic Union?”, December 19, 2007, accessed October 26, 2014. http://www.desiringgod.org/blog/posts/what-is-the-hypostatic-union. Justin Taylor, “Thinking Through Christology”, November 5, 2011, accessed October 26, 2014. http://www.thegospelcoalition.org/blogs/justintaylor/2011/11/05/christology-2/
[ii] Louis Berkhof, Systematic Theology (Grand Rapids: William B. Eerdmans Publishing Company, 1996), 321.
[iii] Douglas Kelly, Systematic Theology: Volume Two (Scotland: Christian Focus Publications, 2014), 183.
[iv] Justin Holcomb, Know the Creeds and Councils (Grand Rapids: Zondervan, 2014), 55.
[v] Ibid., 56.
[vi] John Frame, Systematic Theology: An Introduction to Christian Belief (Phillipsburg: P&R Publishing, 2013), 889.
[vii] Kelly, 186.
[viii] William Ames, The Marrow of Sacred Divinity (London: Edward Griffin, 1642), 77.
[ix] Frame, 896.
[x] John Owen, The Glory of Christ (Carlisle: Banner of Truth, 2013), 105.