In order for any of Adam’s fallen race to be saved, God must come and rescue us from the consequences of our sin. God does so in the person of Jesus Christ, through whom God reveals his justice and mercy. In Jesus Christ, God takes to himself a true human nature and comes to earth to do for us those very things sinners cannot do for themselves—fulfill all the righteous requirements of the law and provide an all-sufficient sacrifice for sin. This is why we must believe and confess that Jesus Christ is fully God and fully man. Yet, we must also believe and confess that Jesus Christ remains but one person. But how can this be? How can two distinct natures–one human and one divine–co-exist in one person? This very important question brings us to a discussion of what theologians call the “hypostatic union” of Christ—two natures, yet one person.

Article nineteen deals with the two natures in Christ (the divine and the human) and the way in which they are both related and yet remain distinct. The reason this question must be addressed at this point in our confession is because the prior article dealt with the incarnation of our Lord. When the word became flesh so as to save us from our sins, the question necessarily arises, how can God truly take to himself a human nature? And if he does, how can both human and divine natures co-exist in a single person? Thus the question we seek to answer is not something theologians speculate about to give them something to do. Rather, it is a question raised by the biblical data itself. How we understand these two natures and their relationship to each other says a great deal about what God did in Jesus Christ to save us from our sins.

We have already seen that the Bible teaches that Jesus Christ is fully God (article ten) and that in his incarnation, the Word became flesh, taking to himself a true human nature (article eighteen). We saw that when we speak of the Word becoming flesh, we mean that Jesus’ human nature is as truly human as is ours, since he took this human nature from the substance of his mother in the womb of the virgin. This is clear from the numerous Bible verses cited in article eighteen which teach that Jesus did indeed come to earth in the flesh. Furthermore, the New Testament tells us that Jesus became tired and needed sleep and food. Jesus experienced the full range of human emotions, from sorrow and compassion to joy.1 And then we see our Lord’s humanity most supremely exemplified by the fact that Jesus Christ shed RH typeable blood on the cross to redeem us from our sins. But even as our Lord was fully human—like us in every way except without sin (Hebrews 4:15)—Jesus remained fully God.

As a follow-up to article eighteen, there are three main points covered by article nineteen of our confession.2 The first point to be addressed is that the person of the eternal son is truly united with the human nature. In the incarnation the Word really and truly took a human nature to himself. If Jesus did not draw his human nature from his mother, then he did not take our nature, and therefore, he cannot redeem our flesh. As we saw last time, this was the error of certain Anabaptists living at the time our confession was written (1561). They believed that God created Jesus’ human nature in the virgin’s womb, just as God created Adam in Eden. They spoke of Mary as a kind of conduit through which the God-man came to earth. But then, this denies that Jesus took to himself a true human nature. The consequence of this is grave—Jesus cannot save us from our sins, because he was not truly one of us.

Having set out the fact that Jesus did indeed possess a true human nature without ever ceasing to be God, our confession affirms what the Bible does—that these two natures (divine and human) are united in a single person, Jesus Christ. But how can this be? And what does it mean for us and for our salvation? Does Jesus have both a human and a divine will? If so, which one is in charge? Did the divine Logos take up residence in a human body so that Jesus is controlled (or directed) by the divine nature? How can Jesus not have two personalities–one divine and one human? These are very real and important questions and need to be tackled now that we have considered the fact of the incarnation.

The second point made by our confession is that both natures retain their distinct properties. The divine nature does not subsume the human nature, nor does the divine nature cease to be divine. Nor is the human nature deified in any sense. Neither can we say the two natures combine with one another so that in the incarnation we have a mixture of humanity and deity. As we have already seen in article one, God is immutable and does not change either as to his will or his essence. Therefore, when we speak of the two natures in one person, we should be clear that in the incarnation the divine nature never undergoes any essential change, although a true human nature is added.3

Finally, our confession makes the point that Jesus Christ was very man and very God so that we might be saved from our sins and that human nature might be truly redeemed. The doctrine of the two natures is not some idle speculation. Adam sinned in Eden, both in his own person and on behalf of the entire human race. Therefore, someone must undo the consequences of his rebellious act. That someone must be man so as to obey the covenant of works which Adam broke and so as to make payment for human sin. But he must also be able to make a payment sufficient to remove both the guilt of Adam’s sin as well as our own, thereby satisfying divine justice. To provide such a payment, he also must be God. And the only way these things can be accomplished is through one person—the God—man.

The fact of our Lord’s incarnation brings us to a discussion of the two natures of Christ and the way in which they are related. As you can gather, this has long been a controversial subject in the church and the speculation about the relationship between the two natures in Christ has been an unfortunate source of both heresy and schism.

From the very beginning, Christians have struggled with this subject. It is perfectly clear from the biblical evidence that Jesus is fully God. That the early church clearly understood this to be the case, can be seen in the ancient origin of the Apostle’s and Nicene Creeds, which bear witness to the fact that Christians have always confessed that Jesus is the Son of God. But the question as to how this can be true has been a source of controversy and speculation. It is also taught in the Bible that Jesus took to himself a true human nature, but the Bible repeatedly speaks of Jesus as one person. Take, for example, the fact that the Bible doesn’t say that Jesus’ human nature suffered on the cross and that the divine nature didn’t—although this is the case. What the Bible says is that Jesus suffered on the cross. This gives us a clue as to how we must handle the two natures and the way in which they are related.

One set of problems regarding the two natures arose among those early Christians who were trichotomists. Trichotomists erroneously believe that men and woman are a body, a soul and a spirit. If true, (and it is not) then it was easy to argue that since Jesus was truly human then he had a body and soul, but since he was also divine, the divine Logos took the place of the human spirit. Known as Apollonarianism, this view was condemned as a heresy by the council of Constantinople in 381 AD.4

Another error which popped up was that of the Alexandrian school in Egypt, in which it was argued that the human nature of Jesus Christ was fused in some way into the divine nature. This is similar to the view currently held by Lutherans, in which it is argued that certain attributes of the divine nature are communicated to the human nature after Christ’s ascension.5 It is on this ground that our Lutheran friends argue that Christ’s human nature is now omnipresent, which explains how Christ’s human nature can be “in, with and under” the bread when the church celebrates the Lord’s Supper. The Reformed have always replied to this notion by saying, “if a human nature has divine properties communicated to it and is omnipresent, then it is no longer human, but a third thing, a tertium quid.” If divine properties can be communicated to a human nature, then that nature is no longer really human.

In reaction to the teaching of the Alexandrians, the Bishop of Constantinople, Nestorius, denied that the two natures of Christ are united in a single self-conscious personality, so that while there were two natures in Christ, they exist side by side without any real union between them. Some have said that the view of Nestorius amounts to the two natures of Christ relating to one another like two boards glued together–they don’t, except in an artificial way. And then we have an over-reaction in the opposite direction with yet another heresy, this time taught by the monk Eutychus, who argued that the there is only one nature in Christ, that of the incarnate Word. This leads to the so-called monophysite heresy–which is that Jesus has only one fusis, or one nature, not two.6

All of this continuing controversy led to the famous formulation of the Council of Chalcedon in 451, which determined the parameters by which the two natures and their relationship should be understood by orthodox Christians. According to the formula of Chalcedon: “We also teach that we apprehend this one and only Christ-Son, Lord, only-begotten–in two natures; and we do this without confusing the two natures, without transmuting one nature into the other, without dividing them into two separate categories, without contrasting them according to area or function. The distinctiveness of each nature is not nullified by the union. Instead, the `properties’ of each nature are conserved and both natures concur in one `person’ and in one reality (hypostasis). They are not divided or cut into two persons, but are together the one and only and only-begotten Word (Logos) of God, the Lord Jesus Christ. Thus have the prophets of old testified; thus the Lord Jesus Christ himself taught us.”

Like the doctrine of the Trinity–which is beyond human comprehension–so too with two natures of Christ the church has seen fit to say what cannot be said, as opposed to attempting to define what the Bible assumes. While we cannot say how the two natures are united–this remains a mystery–we can say that there is one person with two natures (one divine, one human), that we cannot divide them, confuse them, change them, or contrast their functions. We eliminate all such extra-biblical speculation and then affirm that Jesus Christ has two natures which exist in one person. The reason for this is simple–this is how the Bible speaks of our Lord.

This brings us to the first point of our confession, that the person of the Son is really and truly united to the human nature.

Our confession puts it this way. “We believe that by this conception the person of the Son of God is inseparably united and joined with the human nature, so that there are not two sons of God, nor two persons, but two natures united in one single person.” There are a number of proof texts cited by our confession to prove this very important point. The first batch come from the gospel of John. In John 1:14, the apostle states, “The Word became flesh and made his dwelling among us. We have seen his glory, the glory of the One and Only, who came from the Father, full of grace and truth.” This indicates that the Word really and truly became flesh, without at any time ever ceasing to be the Word. In fact, in John 10:30, Jesus is recorded as making the rather remarkable statement, “I and the Father are one.” Such an assertion can only make sense if Jesus is the God-man.

Then there are a number of verses found in the writings of Paul. In Romans 9:5, while speaking of Israel, Paul says of our Lord, “Theirs are the patriarchs, and from them is traced the human ancestry of Christ, who is God over all, forever praised!” Thus our Lord can trace human ancestry, while at the same time be described as “God over all.” Two natures, one person. One of the most important of these assertions about our Lord taking to himself a true human nature is a passage we have already considered, Philippians 2:6-8. Paul says that “Christ Jesus: Who, being in very nature God, did not consider equality with God something to be grasped, but made himself nothing, taking the very nature of a servant, being made in human likeness. And being found in appearance as a man, he humbled himself and became obedient to death–even death on a cross!” Jesus is fully God, fully man and but one person. Yet, another important verse is also found in the writings of Paul (Colossians 2:9). “For in Christ all the fullness of the Deity lives in bodily form.”

From such texts it is clear that Jesus Christ (who was God from all eternity) assumed true human nature, while remaining truly God. There is no evidence (direct or otherwise) anywhere in the Bible that Jesus had dual personalities or conflicting wills. There is no distinction between an “I” and a “thou” in the person of the mediator. Jesus never speaks of himself in the plural, as God does, say in Genesis 1:26. In fact, in those passages we have just read from John and Paul, the two natures are clearly set forth, but it is self evident that they are united together in one person.7

Then, there are a number of passages in the New Testament, in which attributes of one nature are predicated of the whole person. Take for example Acts 20:28—“Keep watch over yourselves and all the flock of which the Holy Spirit has made you overseers. Be shepherds of the church of God, which he bought with his own blood.” Luke speaks of Jesus Christ’s death as that of God purchasing the church with his own blood, blood which was RH typeable because that blood (God’s) was also truly human.

All of this means that the speculation of the early church about these matters, is only that, so much speculation. The fact of the matter is the Word took to himself a true human nature, such that there is but one person with two natures. We must not divide these natures (“well, that’s just the divine nature, speaking, or praying or doing”) nor should we blend them (Jesus is one person because the divine and human natures have been mixed together), nor should we argue that the human nature becomes divine or the divine nature becomes human. This is why we speak of Jesus as the God-man and leave it at that.

The second point made by our confession is that the two natures of Christ retain their unique properties. On the one hand, this is a response to the view of the Lutherans, who teach that a real transference of the attributes of one nature to the other is the only way to secure a unity of the person, on the other, it is a rejection of all those ancient heresies, such as that taught by the monophysites, mentioned earlier.8

Our confession states that “Each nature retains its own distinct properties,” before listing a number of reasons as to why this is the case. “[Our Lord’s] divine nature has always remained uncreated, without beginning of days or end of life (Hebrews 7:3), filling heaven and earth. His human nature has not lost its properties; it has beginning of days and remains created. It is finite and retains all the properties of a true body. Even though, by His resurrection, He has given immortality to His human nature, He has not changed its reality, since our salvation and resurrection also depend on the reality of His body. However, these two natures are so closely united in one person that they were not even separated by His death. Therefore, what He, when dying, committed into the hands of His Father was a real human spirit that departed from His body. Meanwhile His divinity always remained united with His human nature, even when He was lying in the grave. And the divine nature always remained in Him just as it was in Him when He was a little child, even though it did not manifest itself as such for a little while.” All of these assertions are drawn directly from the biblical proof texts listed in the confession. This is the plain teaching of Holy Scripture.

The primary point made by the author of our confession is that Reformed Christians stand squarely in the Catholic tradition regarding the two natures of Christ, and therefore well within the boundaries set out in the Formula of Chalcedon. Not only are we not Anabaptists—with a willy-nilly Christology in many cases–but as Reformed Christians we are reluctant to follow Luther on this point and to argue as Lutherans do, that certain divine attributes are communicated to the human nature, such as ubiquity (omnipresence).9 Furthermore, we clearly reject the philosophical speculation found throughout much of the ancient church about this matter. The Logos did not adopt a human nature and replace either the soul or the spirit, since the human nature of Jesus is fully intact, with both self-consciousness and free-will, and yet in such a way as to be in perfect union and harmony with the divine Logos.

Thus our Lord’s human nature is not lacking in anything essentially human, despite the fact that there is a real union with the divine nature in the person of the Son. We need to be clear here–the degree to which Jesus’ true human nature is lacking or subsumed by the divine nature is the decree to which Jesus does not redeem human nature. Thus, we follow the lead of our confession and simply affirm that Jesus has two natures (one fully human and one fully divine), a human will and a human personality in union with the Logos, so that as we see throughout the pages of the New Testament, there is one person, Jesus of Nazareth, the God-man, who speaks and acts as a single person. Whatever properties may be ascribed to either nature (human or divine), are simply ascribed to the person. In doing this, we are freed from the kinds of speculative questions raised earlier and, more importantly, we speak as does the Bible itself.

Third, our confession addresses the reason why preserving the distinction and understanding the union of these two natures is so important.

Our confession concludes by stating: “For this reason we profess Him to be true God and true man: true God in order to conquer death by His power; and true man that He might die for us according to the infirmity of His flesh.” If Jesus does not assume a true human nature, then we are not saved, because God has not redeemed our fallen nature. But if Jesus is not fully God, then what is the difference between his death and the death of any other lost and fallen human sinner? Why does this death save, when the death of no one else can? No, this death saves, because Jesus is fully God.

This is clearly taught in Holy Scripture. In Psalm 130:3, we read, “If you, O LORD , kept a record of sins, O Lord, who could stand?” Obviously, no one. Well, at least no one with a record of sins. Then in Psalm 49:7-10, we read,
No man can redeem the life of another or give to God a ransom for him– the ransom for a life is costly, no payment is ever enough–that he should live on forever and not see decay. For all can see that wise men die; the foolish and the senseless alike perish and leave their wealth to others.
Since no man can make a sufficient payment for the debt of sin, God himself must provide a payment which is sufficient if any are to be saved. And this God does in the person of his son–Jesus, the God7 man. This, then, is why this topic is so important. It also sets the stage for what follows in article twenty of our confession, a discussion of the cross and the satisfaction of God’s just demands.

As we conclude, what should we take with us from this discussion to better enable us to live lives of gratitude before God?

The first thing is that the doctrine of the two natures reminds us of the lengths to which a gracious God must go to save us from our sins. Given the fact of human sin—sin, which by the way, is a complete affront to the holy majesty of God—there is no possible way for men and women to be delivered from that sin apart from the incarnation of our Lord. Since it is the eternal Son of God, the Word, who became flesh, this forces us to deal with the two natures of Christ and the way in which they are related even though this is not a topic the Bible addresses in precisely these terms. Since it was human nature which sinned, it was absolutely necessary for God to come to earth in the person of Jesus Christ so that human nature might save us. The debt we owe has to be paid by one of us. The punishment involved in the curse (death) required the ability to suffer in body and soul. For such a penatly to be paid, this required the Word to become flesh.

And yet, at the same time, if we are to be redeemed from our sin, the redeemer must himself be without the guilt of sin so that he could in fact make a sacrifice for sins on behalf of others—those he came to save. This is why Jesus was miraculously concieved in the womb of the virgin by the power of the Holy Spirit, so that he was free from the guilt of Adam’s sin. This is also why Jesus subjected himself to the law of God, to earn a justifying righteousness for his people through his own perfect obedience. This is why Paul calls Jesus the second Adam. Jesus does not give into temptation like Adam did. He obeys God’s command, unlike Adam. He earns the crown of life which Adam failed to do. Jesus did all of those things, perfectly, and he did them as someone who was truly human.

But there is much more here to consider. Given the fact that Jesus was truly human, he knows the weakness of our human nature. He knows the temptations we all face–for he has experienced all of them himself, yet without sin. Jesus knows what it is to suffer and die. He knows what we endure when he calls us to go without, as well as when he calls us to times of testing and trial. And yet, since he is without sin, Jesus remains a perfect example for us to follow.10

But no human sacrifice can pay off the infinite debt we owe to the holy God. The sacrifice for our sin must be made by some one who’s death can actually pay the debt. Then, there is the fact that no human can apply their sacrifice or obedience to another so as to pronounce forgiveness. Only God can apply the fruits of Jesus’ redemptive work to others under the terms of a covenant of grace, which he alone can establish on his oath. This is why Jesus must also be fully God. As our catechism puts it in Lord’s Day
Five, questions 12-15:
12 Q. According to God's righteous judgment we deserve punishment both in this world and forever after: how then can we escape this punishment and return to God's favor?
A. God requires that his justice be satisfied. Therefore the claims of his justice must be paid in full, either by ourselves or another.
13 Q. Can we pay this debt ourselves?
A. Certainly not. Actually, we increase our guilt every day.
14 Q. Can another creature—any at all—pay this debt for us?
A. No. To begin with, God will not punish another creature for what a human is guilty of. Besides, no mere creature can bear the weight of God's eternal anger against sin and release others from it.
15 Q. What kind of mediator and deliverer should we look for then?
A. One who is truly human and truly righteous, yet more powerful than all creatures, that is, one who is also true God.
Finally, the doctrine of the two natures of Christ means that since Jesus is truly man, he truly redeems human nature—which by the way, he took into heaven when he ascended on high. Not only do we have hope that the Son of God will redeem our souls, the two natures in hypostatic union also means that God will redeem our bodies as well. For Jesus not only has paid for our sins and provides us with a perfect righteousness, but he is in heaven right now in a body of glorified flesh–a body in which he will return to raise the dead, judge the world and make all things new. Because our Lord has redeemed our flesh, we are certain that our flesh will likewise be transformed so that we might live with him forever and ever.

This is why we must believe and confess Jesus Christ to be true God and true man, yet one person. For Jesus came to save us from our sins and to earn a perfect righteousness by perfectly obeying the law of God. But the Word also became flesh to redeem human nature–and this required him to become like us in every way, yet without sin. Thus, when we speak of being saved–we mean much more than the salvation of our souls. We means the redemption of our whole person–body and soul. This is why we profess him to be true God and true man. Amen!

1See the fascinating essay by B. B. Warfield, “The Emotional Life of Our Lord,” in The Person and Work of Christ (Phillipsburg: Presbyterian and Reformed, 1950), pp. 93-145.
2Beets, The Reformed Confession Explained, p. 153. See the discussion in DeJong, The Church’s Witness to the World, Vol. 2, p. 76.
3Berkhof, Systematic Theology, p. 323.
4Beets, The Reformed Confession Explained, p. 154.
5Beets, The Reformed Confession Explained, p. 154. Cf. Martin Chemnitz, The Two Natures in Christ, trans., J. A. O. Preuss (St. Louis: Concordia Publishing House, 1971).
6Beets, The Reformed Confession Explained, p. 154.
7Berkhof, Systematic Theology, p. 323.
8Berkhof, Systematic Theology, p. 325; Beets, The Reformed Confession Explained, p.156.
9Cf. Berkhof’s discussion of the Lutheran view in, Systematic Theology, pp. 325-327.
10 Berkhof, Systematic Theology, p. 319.