The Heart of It All: The Incarnation (Part 2)

July 5, 2011

by Peter Amsterdam

Audio length: 15:54

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(For an introduction and explanation regarding this series overall, please see The Heart of It All: Introduction.)

The quest to theologically define the person of Jesus and His human and divine natures mainly occurred in two time periods: firstly, in the fourth and fifth centuries, and then secondly in the nineteenth and twentieth.

Once the doctrine of the Trinity was developed and officially settled on, the next theological focus was on the two natures of Christ. (1) As God, He had a divine nature, and (2) in being born as a man, He also had a human nature. As we’ve seen, the Nicene Creed states that Jesus is truly God and truly man. The questions which arose from this were regarding how the person of Jesus of Nazareth could have both natures and how those natures related to each other. Was one nature dominant? Did the divine nature take over the human? Did the two natures combine into one? How did it work?

Inadequate definitions of the nature of Jesus

In the fourth and fifth centuries, a number of bishops and other church leaders put forth their models of how they felt it worked. The problem was that these models were inadequate in that they all failed to keep the divine and human natures separate and intact and/or they concluded that there were two persons in Jesus.

I’ll touch briefly on the main inadequate models. It’s beneficial to know this information as it’s part of the historical development of Christianity, and it helps us gain a deeper understanding of our faith. It’s useful especially when challenged with questions or faced with those who promote untrue doctrine. The first two, Docetism and Ebionism, arose very early in Christianity, in the first and second centuries. The others arose in the fourth and fifth centuries.

Docetism denied that Jesus was human. Docetists felt the good God couldn’t be joined to evil flesh. They considered that Jesus’ life, birth, suffering and death were all an illusion, a mirage, and not real. Thus they denied the reality of Jesus’ humanity.

(Docetism was refuted by the Apostle John in 1 John 4:2–3: “By this you know the Spirit of God: every spirit that confesses that Jesus Christ has come in the flesh is from God; and every spirit that does not confess Jesus is not from God; and this is the spirit of the antichrist, of which you have heard that it is coming, and now it is already in the world.” Also, 2 John 7: “For many deceivers have gone out into the world, those who do not acknowledge Jesus Christ as coming in the flesh. This is the deceiver and the antichrist.”)

Ebionism stemmed from a form of Christianity that was based on Judaism. Because they couldn’t reconcile Jesus being God with the monotheism of Judaism, Ebionists upheld Jesus’ humanity but denied His deity. They said that He was a man who, because of His strict obedience to the law, became the Messiah and Son of God at the time of His baptism by John the Baptist.

Arianism: As we saw in an earlier article, Arius saw the Logos, the son of God, as a creation of God and therefore not God; thus he denied the deity of Jesus.

Apollinarianism: Apollinarias, a bishop in Laodicea around AD 361, taught that the person of Christ had a human body and a human (animal) soul, but not a human rational soul or mind. Rather, the rational soul or mind that functioned within Him was that of the Logos, God the Son. If this were the case, then Jesus wasn’t fully human, as He didn’t have a human mind, only a human body. As was stated in the previous article, Jesus had to be fully human to be the instrument of salvation to redeem man. One of the arguments used against Apollinarianism was that “what He has not assumed, He has not healed.” In salvation, not only does the human body need to be represented by Jesus, but the human mind/spirit as well.

Nestorianism: Nestorius was the bishop of Constantinople in AD 428. The teaching attached to his name is that Christ was virtually two persons in one body, instead of one person. He argued that there was no true union of the Logos and the man, rather that it was some sort of indwelling. But this isn’t consistent with how the New Testament portrays Jesus. It doesn’t show His human nature as being separate from His divine nature. There is no distinctive personal relationship between His human nature and His divine nature. There is no “I” and “thou” relationship shown, as there is between the different persons in the Trinity. The writers of the Gospels didn’t say Jesus’ human nature did this or His divine nature did that. Jesus is always portrayed as one person, not two.

Monophysitism (also known as Eutychianism): Teaching against Nestorianism, Eutyches (circa AD 378–454) taught that Jesus’ human nature was merged into His divine nature and therefore He only had one nature. The result was that the nature of Jesus was a combination of human and divine natures, meaning that this combination was a third kind of nature that is neither human nor divine. This was considered a confusing or confounding of the natures.

Reality of the natures of Jesus

It’s important to understand that Jesus had two natures: divine and human. But one didn’t absorb the other, and there can be no confusing the natures. So, although there were two natures in Jesus, there was only one person. The natures didn’t exist side by side within Jesus, as that would have made Jesus two people in one body, but rather everything flowed from one personal center. The two natures came together in unity in Jesus, so that He was not God and man, but the God-man, one person.[1]

William Lane Craig gave this brief explanation on this point, “What exactly does it mean to say Christ subsists in two natures? It means that Christ is essentially a divine person who assumed in the incarnation a rational soul and body such as are essential to human beings. He is all that one needs to be to be God and all that one needs to be to be a man.”[2]

As much as one tries to fully understand how the two natures function within Jesus, it’s impossible to know. We can know and understand the concept, as we do that of the Trinity, but not the reality of how it works. Jesus was the only person ever who was the Incarnate God, the God-man. Thus there is nothing within our human experience to compare it to, so there is no way to fully comprehend it.

Jesus’ conception played a role in God becoming “enfleshed.” Mary, His mother, conceived without any male involvement. She was a virgin, betrothed but not yet married to Joseph. It was through the power of the Holy Spirit that Mary was to become pregnant.

The Holy Spirit will come upon you, and the power of the Most High will overshadow you; therefore the child to be born will be called holy—the Son of God.[3]

Jesus was the only man ever conceived without a human father, so it’s not surprising that He would be unique in the sense of being fully man and fully God, with both divine and human natures. His virgin conception was a sign of His deity as well as His incarnation as a man.

I’ll insert a word about Mary here. Mary is called “the mother of God,” from the Greek word Theotokos. She was called this to make it clear that from the moment of conception Christ was God, and thus she was the mother of God. However, this did not mean that she mothered the eternally existing Logos, God the Son, because the Son eternally existed before He was conceived in Mary’s womb. Therefore Mary was the mother of God according to His human nature, according to His manhood.

As William Lane Craig explains, “The Christian doctrine of the Incarnation states that Jesus Christ is God in the flesh. Jesus was thus truly God as well as truly man. He was born of the virgin Mary; that is to say, Jesus had a supernatural conception but a perfectly natural birth. Since Jesus was God in the flesh, his mother Mary is therefore called in the early Christian creeds ‘the Mother of God,’ or the ‘God-bearer.’ This isn’t because God somehow came into existence as a result of Mary’s conceiving or that Mary somehow procreated God. Rather Mary could be called the God-bearer because the person she bore in her womb and gave birth to was divine. Thus, Jesus’ birth in this sense was the birth of God.”[4]

Chalcedonian council and settling the issue

In AD 451 an ecumenical council was convened by the emperor Marcian in Chalcedon (in present-day Turkey) to settle the issue regarding Jesus’ divine and human natures. Over 500 bishops gathered for the council that decided the matter. The council set down parameters under which theological speculation on the question of Jesus’ two natures must operate. The council did not attempt to solve the problem of how the incarnation worked, or how it is possible, but only what can and can’t be said by setting the boundaries within which one could wrestle with the problem.

The council affirmed that:

  • Christ has two natures, one human and one divine, each one complete.
  • He has both a rational soul and a body.
  • He is perfect in manhood and perfect in deity.
  • There is only one person in Christ.
  • The union of the divine nature and human nature are without confusion, without change, without separation, and without division.

In brief, you must not confuse the natures or divide the person. There are two natures but only one person in Christ.

Most theologians, when pointing to the boundaries you must stay within for proper theology on this issue, use the analogy of sailing between two large rocks—on the one side, two natures; on the other, one person. As long as you sail between them, you are safe theologically.

The council did not publish a new creed (there were no more creeds after the Nicene-Constantinopolitan creed), but rather published a definition of the faith, which rejected Apollinarianism, Nestorianism, and Monophysitism. The Chalcedonian definition reads (words in brackets are mine for explanation):

We, then, following the holy Fathers, all with one consent, teach people to confess one and the same Son, our Lord Jesus Christ, the same perfect in Godhead and also perfect in manhood [against Apollinarianism]; truly God and truly man, of a reasonable [rational] soul and body;

consubstantial [having the same substance] with the Father according to the Godhead, and consubstantial with us according to the Manhood;

in all things like unto us [fully human], without sin;

begotten before all ages of the Father according to the Godhead [eternally existent in divinity], and in these latter days, for us and for our salvation, born of the Virgin Mary, the Mother of God, according to the Manhood [showing that she is not the mother of the divinity but of the humanity]; one and the same Christ, Son, Lord, only begotten, to be acknowledged in two natures, inconfusedly, unchangeably, indivisibly, inseparably; the distinction of natures being by no means taken away by the union [against Monophysitism], but rather the property of each nature being preserved, and concurring in one Person and one Subsistence, not parted or divided into two persons [against Nestorianism], but one and the same Son, and only begotten God, the Word, the Lord Jesus Christ; as the prophets from the beginning have declared concerning Him, and the Lord Jesus Christ Himself has taught us, and the Creed of the holy Fathers has handed down to us.

In the centuries after the Council of Chalcedon, a teaching called monothelitism arose. This teaching claimed that while Christ was one person with two natures—thus upholding Chalcedon—there was only one divine-human will, thus two natures but only one will in Jesus. Some saw this as a repudiation of the Chalcedon definition.

In the third Council of Constantinople in AD 681, the church leaders determined that there were two wills in Christ. The wills belong to the two distinct natures of Christ, not to the person. The doctrine of the two wills has been held generally, but not universally, within the church.

This was the final debate of the ancient church on the subject. In later centuries, most notably the nineteenth and twentieth, there was further exploration of the subject, which we will look at in the next article.


Unless otherwise indicated, all scriptures are from the Holy Bible, English Standard Version, copyright © 2001 by Crossway Bibles, a division of Good News Publishers. Used by permission. All rights reserved. Other versions frequently cited are The New International Version (NIV), the New American Standard Bible (NASB), The New King James Version (NKJV), and the King James Version (KJV).


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[1] J. Rodman Williams, Renewal Theology, Systematic Theology from a Charismatic Perspective (Grand Rapids: Zondervan, 1996), 343–44.

[2] William Lane Craig, Fictionalism and the Two Natures of Christ, 2007.

[3] Luke 1:35.

[4] William Lane Craig, The Birth of God, on