“The Word became flesh” (John 1:14). It is, once again, the time of year when the majestic words of the prologue to John’s Gospel will be read in churches throughout the world.

The verses constitute the shortest, but perhaps profoundest, description of the incarnation in the New Testament. And the more you think about them, the profounder they seem to be. John underscores (1) Christ’s eternity (“In the beginning was the Word”) and (2) his deity (“and the Word was God”) in John 1:1. But he also places him “in the bosom/at the side of” God (John 1:18), indeed “towards” or perhaps more vividly “face-to-face with God” (Greek pros ton theon).

“Christology was a life-and-death matter. Missteps could be dangerous. That was true then; it remains true today.”

Here is the mystery of deity incarnate. The wonder of it expands our minds and stretches our spirits: the Word who was face-to-face with God in the glory of eternity (John 17:5, 24) came to be face-to-face with us in this world, marked by temporality, changeability, and the shame of sin. Infinite and finite, eternal and temporal, Word made flesh.

For the first four hundred years of the church’s history, her finest minds probed the significance of these words. How can we understand them? In what terms should we communicate them? Can we press on to the outer circumference of God’s revelation of his Son without falling over the edge into error and even heresy?

Life-and-Death Matter

It was against that background that the early Christian confessions were written, ranging from the New Testament’s “Jesus is Lord” through the Apostles’ Creed, to the Athanasian, Nicene, and Constantinopolitan Creeds of the first four centuries.

Sometimes the early Christian thinkers made mistakes; sometimes they realized their statements were inadequate to safeguard the church. And when you believe, as they did, that martyrdom can never destroy the church but false teaching always will, it is understandable that sometimes discussion and debate reached a fever pitch of emotion, and occasionally harsh actions and reactions followed. It was said that it was impossible to go to the public baths without overhearing debates about the divinity of Christ!

Christology was a life-and-death matter. Missteps could be dangerous. That was true then; it remains true today. After all, isn’t it all-important to you to carefully describe the One you love best?

Four Great Errors

Despite several major efforts to help believers rightly understand and describe what really happened in the incarnation, disagreements, missteps, and divisions continued into the fifth century. To resolve them, in 451 the Emperor Marcian convened a council of some five hundred bishops at Chalcedon (now a district of Istanbul in Turkey). The confession they produced is usually known as the Definition of Chalcedon.

The Chalcedonian theologians were conscious of deviations from biblical orthodoxy that had plagued the church for over a hundred years, and especially of two that had exacerbated recent controversy. Their statement especially took into account errors that were and are associated with the names of four individuals:

• Arius, who died in 336. Arianism is the view that the Lord Jesus Christ is not fully God.
  
• Apollinaris, who died in 390. Apollinarianism is the view that Christ did not really have a human mind, but instead the eternal Logos took its place.
  
• Nestorius, who died in 451. Nestorianism is the view that after the incarnation there were two persons, the divine and the human, united together by a common will (although today it is questioned whether Nestorius himself really held this view).
  
• Eutyches, who died in 456. Eutychianism is the view that after the incarnation Christ had only one nature.
  

Is there really any value in knowing about these people and their theology? You will see that there is if you can spot what they all have in common — something that, if true, would disqualify Christ from being our Savior.

Chalcedonian Definition

So, the Chalcedonian Definition sought to exclude:

• Arianism, because if Christ is less than God, he cannot reconcile us to God.
• Apollinarianism, because if Christ is not truly human, he is not really one with us and therefore cannot act for us as our Mediator.
• Nestorianism, because if there are two persons in Christ and not one, then it is only the human person Jesus who offers himself as a sacrifice to God on the cross. For a divine person cannot die in his divine nature. And even if a human person could act as a redeeming substitute, his single death could never atone for the sins of many. One eye atones only for one eye, one tooth for one tooth, one person for one person. It requires an infinite person to make adequate substitution for the salvation of a multitude that no one can number.
• Eutychianism, because if the two natures of Christ are mixed together into one, then our Lord is no longer truly one of us and cannot therefore function as our substitute.

In each and all of these views, Christ would be disqualified from being our Savior! This background explains why the bishops meeting at Chalcedon wrote the following exalted sentences as their creed:

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; truly God and truly man, of a reasonable soul and body; consubstantial with the Father according to the Godhead, and consubstantial with us according to the manhood; in all things like unto us, without sin; begotten before all ages of the Father according to the Godhead, and in these latter days, for us and for our salvation, born of the Virgin Mary, the Mother of God, according to the manhood; 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, 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; as the prophets from the beginning declared concerning him, and the Lord Jesus Christ himself has taught us, and the Creed of the holy Fathers has handed down to us.

“Within the womb of a teenage girl was the One who upholds the entire universe.”

Notice four major emphases: First, Christ is perfectly and truly God and perfectly and truly man, with a rational soul and a real body. Therefore, the Logos does not take the place of the soul. Second, he is of the same substance as God. Therefore, he is not less than God, but truly God. Third, he is the Son of God eternally begotten by his Father but also made flesh in the womb of the Virgin Mary, the Mother of God. Therefore, he is one person, not two. Fourth, he is now one Person with two natures, divine and human. Therefore, these two natures are never confused with each other, changed into each other, or divisible or separable from each other.

Distinct Natures, Perfectly United

When these two natures are united in Christ, each nature retains its own properties and is distinguished from the other. All the properties of both natures are preserved intact. But since these two natures are united in one person, he can act in each nature in a way appropriate to it. There is not, strictly speaking, a “communication of properties” between the natures, but a union of them in the person of the Son.

Nor is there a moment when these natures are parted from each other (Jesus does not cease to have a divine nature when he dies on the cross; he will never cease to have a human nature). Nor are these natures to be thought of as divided between two persons, but are both possessed by “one and the same” person.

So, there was never a point in our Lord’s life when, in order to accomplish something, he injected some deity into his humanity. Had he done so his humanity would have ceased to be like ours (sin apart), and he would have disqualified himself from being our Savior. No — as John Owen would later state so clearly and well — our Lord lived in and through his human nature in constant dependence on the power of the Spirit to fulfill his calling and ministry, not by mixing together some deity with his humanity.

Testing the Creed

When we were young schoolboys our science master sometimes began a new lesson by dictating to us a “definition” which we would then test by doing laboratory experiments, in order to see how it worked. In a sense we can do the same thing with the Definition of Chalcedon, testing it in the Scriptures. Here are two examples:

Example 1: Jesus tells us that no one knows the time of his coming except the Father. Not even the Son knows the time of his own coming (Mark 13:32)!

“The Son of God has come to our side without leaving the side of his Father.”

Here our Lord speaks in accordance with his human nature. It is not omniscient because it is human, not divine. It does not have direct access to divine knowledge. Christ here acts through his human nature in a way that is consistent with that human nature. But he is “one and the same person” when he speaks. In his divine nature that person is omniscient, but that property is never mixed with the limitations of his humanity to render it omniscient. Indeed, as to his humanity, our Lord remains ignorant: there is something he does not know.

Example 2: In Luke 2:52 we are told that Jesus grew in stature. Normal human nature does that. But he also grew in wisdom. He was wiser when he was twelve than he was when he was nine, and wiser still when he was thirty. Why? Because, unlike divine nature, human nature develops wisdom through learning and experience.

But Luke adds a comment that sometimes startles Christians. Read it slowly: “Jesus increased . . . in favor with God . . .” Do you think of the Son of God in whom you trust as someone who grew in favor with his heavenly Father? If not, you may well have been guilty of one of the missteps (or, embarrassingly, one of the heresies!) listed above.

It is a stunning truth that Luke states here, isn’t it? But it is also wonderful. For some thirty-three years, in our human nature, God’s only begotten Son grew in favor with his Father. As he faced more severe opposition and increasingly harder tests, his obedience expanded into them and he remained faithful. Gethsemane was far harder than the wilderness of Judea.

Genius of the Incarnation

That growth in favor with God continued right up to the day when, in obedience to him, he was willing to enter a no-man’s-land where he no longer experienced the assurance of Psalm 23:4 or the Aaronic benediction’s promise that the face of God would be felt smiling upon him (Numbers 6:24–26). “My God, why have you forsaken me?” was wrung out of a mind overcome by a sense of the wrath of God (Psalm 22:1).

Yet, John 10:17 suggests that since this was the apex of his obedience (Philippians 2:8), the implication of Luke 2:52 is that just at this point his loving Father could have been quietly singing over him,

My Jesus, I love thee.
I know thou art mine. . . .
If ever I loved thee,
My Jesus, ‘tis now.

And for this reason we can sing,

‘Tis mystery all, the Immortal dies.
Who can explore his strange design?
In vain the firstborn seraph tries
To sound the depths of love divine.
Amazing love, how can it be,
that thou, my God, should’st die for me?

“The wonder of deity incarnate expands our minds and stretches our spirits.”

This is the wonder of the incarnation, the genius of the divine design. It will take a human death to undertake the death of humans — the death of an infinite person for a multitude of sinners. And so the Son of God has taken our nature without losing his own identity; the Word has become flesh without ceasing to be eternal Word; he has come to our side without leaving the side of his Father. And in the glorious mystery of his incarnation, and though his life, death, resurrection, ascension, reign, and return in our flesh, the God-man has become and will forever remain our Savior!

In this way the Chalcedonian Definition both illumines and protects our thinking.

Within the Teenage Womb

Were you struck by these words in the Definition: “born of the Virgin Mary, the Mother of God” (theotokos — the God-bearer)?

In a sense, this daring description was the litmus test for the Chalcedonian theologians. It is not that Mary gave birth to a divine nature, but that the One who emerged from her womb was the One who was at the Father’s side, himself God. The Christ is not two persons but “one and the same.” Within the womb of a teenage girl was the One who upholds the entire universe.

C.S. Lewis famously has Lucy respond to Lord Diggory’s comment that the stable in Narnia is bigger on the inside than it is on the outside, “Yes, in our world too, a stable once had something inside it that was bigger than our whole world.” The Chalcedonian fathers spoke of something even more wonderful: In our world too, in a teenage womb, was conceived of her flesh the person who was in the beginning with God and was God, and through whom all things were created.

Whatever the failures and flaws of the Christians of the fourth and fifth centuries, it is worth reflecting on the truths articulated in the Chalcedonian Definition, especially at Christmas. For it helps us to see why we can be grateful for — and satisfied, intellectually, emotionally, spiritually, and humanly, with — the Lord Jesus Christ, our glorious Redeemer: Pleased as man with man to dwell, Jesus, our Immanuel!