What Is the Chalcedonian Definition of the Person of Christ?

Summary

Doctrine Matters with Kevin DeYoung: Detailed Summary

Episode Title: What Is the Chalcedonian Definition of the Person of Christ?
Release Date: July 1, 2025
Host/Author: Crossway – Pastor, bestselling author, and Associate Professor of Systematic Theology Kevin DeYoung
Podcast Description: In this weekly podcast, Kevin DeYoung explores the most significant theological topics, equipping Christians with a deeper understanding of the theology that underpins their faith.

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1. Introduction to the Episode

The episode begins with Kevin DeYoung and his co-host outlining the podcast's mission to equip Christians with a thorough understanding of theology, addressing misunderstood or threatened doctrines throughout church history. The focus of this episode is Christology, specifically examining the Chalcedonian Definition of the Person of Christ.

2. Understanding Christology and the Person of Christ

Kevin DeYoung introduces the central theme: the nature of Christ as both fully divine and fully human. He emphasizes the importance of comprehending how one person can embody two distinct natures without confusion, change, division, or separation.

Kevin DeYoung [00:39]: "We think theologically together because, as the title of the podcast tells you, Doctrine Matters."

3. The Four Heresies Leading to Chalcedon

To appreciate the significance of the Chalcedonian Definition, the discussion delves into four major heresies that emerged in the 4th and 5th centuries, each challenging the orthodox understanding of Christ's nature.

a. Arianism

Arianism, initiated by Arius, contended that the Son of God was not co-eternal with the Father, implying that He had a beginning and was a lesser deity.

Historian [02:37]: "Arianism denies the full divinity of Christ. The Arians may have said that the Son was God, but he was a lesser kind of God."

The Council of Nicaea in 325 AD addressed this heresy by affirming that the Son is homoousias (of the same essence) as the Father, countering Arius's claims.

Theologian [03:35]: "The Son is homoousias, homo meaning same ousias, being or essence."

b. Docetism

Docetism, an umbrella term rather than a specific sect, denied the full humanity of Christ, asserting that He only appeared to be human.

Theologian [03:56]: "Docetism asserts that Christ only seemed to be human."

Apollinarius, a notable proponent, argued that Christ had a divine Logos instead of a human mind to avoid sinfulness, thereby undermining His complete humanity.

Historian [04:24]: "By spirit here he is thinking of rationality in the higher faculties."

c. Nestorianism

Nestorianism, named after Nestorius, the Patriarch of Constantinople, proposed that Christ existed as two separate persons—one divine and one human—rather than a single person with two natures.

Historian [08:02]: "Nestorius was the patriarch of Constantinople. His teachings were condemned in 431 at the Council of Ephesus."

Nestorius objected to the term Theotokos ("God-bearer") for Mary, arguing that she was merely the mother of Jesus’s human nature, not His divine nature.

Historian [09:00]: "So her son, Jesus of Nazareth was and is God, so she's the mother of God."

Cyril of Alexandria countered Nestorius by insisting that without affirming Mary as Theotokos, the Incarnation would fail to truly unite divinity and humanity, jeopardizing salvation.

Theologian [10:34]: "If Mary is not the God bearer, then we must understand the Incarnation as something other than God becoming man."

d. Eutychianism

Eutychianism, associated with Eutychus, reacted against Nestorianism by rejecting the division of Christ’s natures. This extreme reaction led to Monophysitism—the belief that Christ has only one nature, a fusion of divine and human.

Historian [12:28]: "Eutychus taught that there were two natures before the union, but only one nature in Christ after the union."

Eutychianism blurred the distinction between divine and human, creating a third, indistinct nature that compromised both.

Theologian [13:15]: "Jesus is not half God, half man and without separation. So the union in the person is a real organic union, not simply a relational partnership."

4. The Council of Chalcedon and Its Definition

In response to these heresies, the Fourth Ecumenical Council, held in Chalcedon in 451 AD, articulated a precise definition to preserve the orthodox understanding of Christ's dual nature.

Historian [13:40]: "Chalcedon in 451 is affirming and how it's pushing aside all of these errant views of the person of Christ."

The Chalcedonian Definition states that Jesus Christ is "at once complete in Godhead and complete in manhood," affirming both natures without mixing, dividing, or altering them.

Historian [14:39]: "Chalcedon is extremely careful and necessary."

Key elements of the definition include:

• Homoousios with the Father: Affirming the divine nature.
• Homoousios with Us: Affirming the human nature, similar to humanity except for sin.
• Theotokos: Affirming Mary as the God-bearer.
• Without Confusion, Change, Division, or Separation: Ensuring the distinctness of each nature.

Historian [14:58]: "Without confusion, without change, without division, without separation."

5. Significance of the Chalcedonian Definition

The Council of Chalcedon’s definition was pivotal in maintaining the balance between Christ’s divinity and humanity. It safeguarded the belief that:

• Jesus is fully God and fully man: Each nature retains its unique properties.
• The union is real and organic: Not merely relational or symbolic.
• Salvation through One Person: Emphasizing that salvation is accomplished by the unified person of Jesus Christ, not by two separate entities.

Theologian [16:09]: "All of this matters for us and for our salvation. We are not saved by two natures working together, but by one divine Person, the Lord Jesus Christ."

6. Conclusion and Implications for Faith

Kevin DeYoung underscores the enduring importance of the Chalcedonian Definition in Christian theology and salvation. By affirming the true humanity and divinity of Christ in one person, believers can confidently rest in the efficacy of Christ’s work for their salvation.

Theologian [16:35]: "We are saved by one divine Person, the Lord Jesus Christ, consisting of a human nature and a divine nature."

7. Additional Resources

For listeners seeking to delve deeper into the topics discussed, Kevin DeYoung recommends his book Daily Doctrine, available in both print and audio formats through Crossway.org. He also encourages engaging with pastors or trusted friends for further theological exploration.

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Notable Quotes with Timestamps:

• Kevin DeYoung [00:39]: "We think theologically together because, as the title of the podcast tells you, Doctrine Matters."
• Theologian [03:35]: "The Son is homoousias, homo meaning same ousias, being or essence."
• Historian [08:02]: "Nestorius was the patriarch of Constantinople. His teachings were condemned in 431 at the Council of Ephesus."
• Theologian [10:34]: "If Mary is not the God bearer, then we must understand the Incarnation as something other than God becoming man."
• Theologian [13:15]: "Jesus is not half God, half man and without separation. So the union in the person is a real organic union, not simply a relational partnership."
• Theologian [16:09]: "All of this matters for us and for our salvation. We are not saved by two natures working together, but by one divine Person, the Lord Jesus Christ."
• Theologian [16:35]: "We are saved by one divine Person, the Lord Jesus Christ, consisting of a human nature and a divine nature."

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This comprehensive summary encapsulates the key theological discussions from the episode, providing listeners and readers with a clear understanding of the Chalcedonian Definition and its importance in Christian doctrine.

Transcript

[Kevin DeYoung]

Hello, I'm Kevin DeYoung, pastor at Christ Covenant Church in Matthews, North Carolina, and.

[Co-host]

You are listening to Doctrine Matters.

[Kevin DeYoung]

We want this podcast to equip Christians.

[Co-host]

With a better understanding of the rich.

[Kevin DeYoung]

Theology that undergirds our faith.

[Co-host]

And hopefully along the way, we'll be.

[Kevin DeYoung]

Looking at some that have even been misunderstood or maybe threatened in the church's history. We'll point out the biblical evidence, the arguments, and work together to reshape our.

[Co-host]

Thinking, be transformed by the renewal of.

[Kevin DeYoung]

Our minds with scripture and reason as.

[Theologian]

We think theologically together.

[Kevin DeYoung]

Because, as the title of the podcast tells you, Doctrine Matters this week, as.

[Theologian]

We continue with Christology, want to bring together a number of themes and ideas that we've talked about already. So we're thinking about the person of Christ and. And one person, two natures. How do we understand we're going to land at the Chalcedonian definition, 451, the Council of Chalcedon, the Fourth Ecumenical Council, as it's called.

[Historian]

But in order to understand what Chalcedon.

[Theologian]

Is affirming, let's try to summarize the various heretical options that popped up in the 4th and 5th century in particular. And we've already hit on some of these. So Arianism. And here's what I want you to think about as we think about each of these. If you had a circle on a.

[Historian]

Chalkboard and you drew a line right down the middle. Very crude illustration, I understand.

[Theologian]

And on one side you wrote a D for divinity, and on the other side of that line in the circle, you wrote an H for humanity. You want to think about how to conceive of Christ. One person, that circle with two natures. Now, just dividing a line between the two halves of the circle is a little misleading. It makes it sound like there's half of Jesus which is divine, and half of Jesus is human. But just for the sake of a visual picture in your mind, because each one of these heresies is going to either deny the humanity or the divinity, or the union of the two, or the legitimacy of both of them. So here's what I mean. First, Arianism talked about Arius and his.

[Historian]

Contention that there was when the sun.

[Theologian]

Was not, Arius understood incorrectly, but his main contention was that begottenness implies a beginning. If you are begotten. And the Son of God is by.

[Historian]

Definition a Son is begotten of a Father.

[Theologian]

And so the eternal Son of God was begotten. And therefore he is not the eternal Son of God, maybe even created outside of time, but he had A beginning. Arianism therefore denies the full deity of Christ. The Arians may have said that the Son was God, but he was a lesser kind of God. He wasn't God in the same way.

[Historian]

Of the same stuff, of the same essence as God. The Father.

[Theologian]

Council of Nicaea famously addressed Arianism in.

[Historian]

Particular and made that central affirmation that.

[Theologian]

The Son is homoousias, homo meaning same ousias, being or essence.

[Historian]

He is of the same essence as the Father.

[Theologian]

So you have Arianism, which is calling into question the full divinity of Christ. Now a second heresy, Docetism. Now, there wasn't someone named Docet like.

[Historian]

There was someone named Arius.

[Theologian]

In fact, there wasn't a group called the Docetus per se. But this is an umbrella term to describe various heresies which denied the full humanity of Christ. Dokeo is a Greek word meaning to seem. So Docetism asserts that Christ only seemed to be human.

[Historian]

In particular, some would deny that he had a human mind.

[Theologian]

In Apollinarius, for example, his solution was to say man is tripartite body, soul and spirit. The Spirit thought Apollinarius was the seat of sin. And by spirit here he is thinking of rationality in the higher faculties. What he called spirit, we might say more as mindfulness. So if Christ had a completely human mind, then he couldn't be of one mind with the Father, he's arguing, and.

[Historian]

He would be able to sin. Consequently, Apollinarius reason Christ must have had.

[Theologian]

The divine Logos in place of a human mind. So all of this is to deny the full humanity of Christ. The Son of God, in Apollinarius thinking, took to himself an incomplete human nature.

[Historian]

Pollinarius saw the Incarnation as the Word.

[Theologian]

Becoming flesh rather than the Word becoming man.

[Historian]

Christ was the substantial union of one heavenly element, the Logos, and one earthly element, a human body.

[Theologian]

So you see the difference there. Yes, he took on human flesh, it was a human body, but he was not man.

[Historian]

Apollinarius said, he is not man, though like man, for he is not consubstantial with man.

[Theologian]

In the most important element, that Latin word consubstantial, and that's our English word that's just getting this cone with substance. So it's similar to Homoosias, which is same substance.

[Historian]

There we're having this English word, consubstantial.

[Theologian]

Apollinarius is denying that Christ was consubstantial.

[Historian]

With us, that he had the same nature as us.

[Theologian]

So this is under this term. And Apollinarius is one of the major proponents under this umbrella term Docetism. Now, of course, he doesn't go around in saying, I want you to be a part of the Docetus. And here I am espousing a heresy. Of course, heretics don't see themselves that way. Whereas Arianism denies the full deity, that.

[Historian]

The Son is consubstantial with the Father.

[Theologian]

Docetism. And as we've looked at this one proponent, Apollinarius, he denied that Christ was.

[Historian]

Consubstantial with us, full humanity.

[Theologian]

Well, two more before we get to Chalcedon.

[Historian]

The third heresy, Nestorianism.

[Theologian]

So if the debate with Arianism clarified that the Son is fully God, sharing the same essence with the Father, and.

[Historian]

Then the debate with Docetism or Apollinarianism.

[Theologian]

Clarified that the Son is fully human, not just appearing to be a man. And you can in a way think of the First Ecumenical Council dealing explicitly with Arianism, 325 Nicaea and the Second Ecumenical Council 381, some ways responding to Apollinarius and to Docetism. Now, it's not quite that simple, but just for thinking about it, you have these first four ecumenical councils which are really dealing with these four variations of the truth, which in fact are heresies. So arianism dealt with First Ecumenical Council 325, 381 Second Ecumenical Council in Constantinople dealing with Docetism, at least in some ways. And then we come to nestorianism in.

[Historian]

The Third Ecumenical Council. It is in Ephesus, in 431. So here the issue following these two disputes came a second pair of Nestorianism.

[Theologian]

Which held that the two natures were divided, and Eutychianism. We'll come back to that in a.

[Historian]

Moment, which held the two natures were mixed. So Nestorianism, let's start there. Nestorius was the patriarch of Constantinople. His teachings were condemned in 431at the Council of Ephesus.

[Theologian]

So that's the third ecumenical council.

[Historian]

His error grew out of his concern.

[Theologian]

That people were calling Mary Theotokos, the God bearer.

[Historian]

It has happened since Nestorius, and most.

[Theologian]

Likely was happening in his day too.

[Historian]

That people took the step from Mary.

[Theologian]

The bearer of God, to Mary, the.

[Historian]

Divine Mother of God. And that is a problem.

[Theologian]

Theotokos is a proper term, but only.

[Historian]

With the proper qualifications. The emphasis must be on the Son, not on Mary.

[Theologian]

So this was a Christological debate. Now, some heard it as Mary the Mother of God, which is a way of describing, but more technically, I want to say Mary, the bearer of God.

[Historian]

Say Mary the mother of God.

[Theologian]

Well, yes, her son, Jesus of Nazareth was and is God, so she's the mother of God. But Nestorius objected to this title. He could admit that Mary bore someone and that the someone was Jesus, but he reckoned that she gave birth to.

[Historian]

The human nature of Christ.

[Theologian]

After all, divinity is eternal. How can divinity come out of the body of Mary?

[Historian]

So his solution was to argue for.

[Theologian]

A kind of dividing wall between the two natures. He knew the Son was a man.

[Historian]

And a whole man. Mary therefore must have been the mother of only Jesus.

[Theologian]

She brought forth a man who was accompanied by the Logos. The two natures therefore existed more like a partnership than a union, than a union of being. So if you go back and you think of a circle, it's got a line down the middle.

[Historian]

It's got a D for divinity on.

[Theologian]

One side, an H for humanity on the other side. If Arianism X's out the divinity not fully divine and Docetism X's out the H, she's not fully human like us, then Nestorianism pushes the two halves apart so that it's a sympathetic union. It's a kind of partnership, but it's not a true ontological union. Nestorius was opposed by Cyril of Alexandria, who made two decisive arguments in favor of Theotokos. He said, if Mary is not the God bearer, then we must understand the Incarnation as something other than God becoming man.

[Historian]

You have rather God coming alongside man. And if God just comes alongside man.

[Theologian]

Then how can we be saved? His second argument was to say, if Mary is not the God bearer, then the relationship of Christ to humanity is changed.

[Historian]

See, Nestorius's problem was not with the two natures.

[Theologian]

He said, yes, human and divine.

[Historian]

Got it.

[Theologian]

His problem was with the one person. Christ is fully God and fully man in historianism, but he didn't constitute a single person. Instead of two natures in a single.

[Historian]

Self conscious person, the two natures are.

[Theologian]

Next to each other in a moral and sympathetic union. But if the two natures are divided in any way, there is no way.

[Historian]

For the single person of the Son.

[Theologian]

To lay his hand on us both. And then a final heresy. Now there's lots more than this, but just these four major categories.

[Historian]

The fourth is Eutychianism. Eutychus was an ancient monk at a monastery in Constantinople.

[Theologian]

Like Nestorius, it's. It's hard to determine exactly what he taught and many ideas get attached to his name. But insofar as this is Utychianism, here's what Eutychus was saying.

[Historian]

He had a Strong anti Nestorian bias. This is instructive.

[Theologian]

Heresies all often arise because they are.

[Historian]

Rightly concerned about some other error. And in trying to combat one error.

[Theologian]

They are not as nuanced or as.

[Historian]

Guarded or as precise as they should.

[Theologian]

Be in setting aside that error, and then they end up making other errors. So Eutychianism, not wanting to fall into the trap of Nestorianism, dividing Christ's humanity from his divinity, Eutychianism comes down and ends up with a kind of mixture and confusion. So Eutychus taught that there were two.

[Historian]

Natures before the union, but only one.

[Theologian]

Nature in Christ after the union of his divinity and humanity.

[Historian]

So divinity, humanity come together.

[Theologian]

And Eutychus then ends up teaching a kind of Monophysitism or Monophysite heresy. Mono meaning one, phusis, meaning nature, the.

[Historian]

Belief that Christ only had one nature.

[Theologian]

Sometimes it's referred to with this Latin phrase, a tertium quid, which means a third thing. Because in Eutychianism you have a human.

[Historian]

Nature, you have a divine nature.

[Theologian]

But they come together and their distinct properties then are mixed and confused, and.

[Historian]

They end up a third thing. So the person of the Son of.

[Theologian]

God with the two natures is like mixing yellow and blue, and then you stir it up and you get green.

[Historian]

That is a third thing. Eutychianism is then addressed with all of.

[Theologian]

These other heresies at the fourth Ecumenical Council in Chalcedon. And you need that background. Arianism, Docetism, Nestorianism, Eutychianism.

[Historian]

So you can hear what Chalcedon in.

[Theologian]

451 is affirming and how it's pushing aside all of these errant views of.

[Historian]

The person of Christ. Therefore here's the definition. Following the Holy Father, as we all, with one accord, teach men to acknowledge one and the same Son, our Lord.

[Theologian]

Jesus Christ, at once complete in Godhead and complete in manhood, truly God and.

[Historian]

Truly man, consisting also of a reasonable soul and body.

[Theologian]

So that's against Apollinarius of one substance with the Father. And there's the Greek word homoosion, of.

[Historian]

One substance with the Father as regards.

[Theologian]

His Godhead, and at the same time of one substance with us regarding his manhood.

[Historian]

And importantly, the Chalcedonian definition uses homoousios there, that he is both homoousios with the Father and homoousios of the same.

[Theologian]

Essence with us, like us in all respects apart from sin, as regards his.

[Historian]

Godhead, begotten of the Father before the ages, but yet as regards his manhood, begotten for us men and for our salvation of Mary the Virgin, the God bearer.

[Theologian]

There's the word Theotokos, one in the.

[Historian]

Same Christ Son, Lord only begotten, recognized in two natures. And then here is the very heart of the Chalcedonian definition with these four.

[Theologian]

Phrases without confusion, without change, without division, without separation. So without confusion. So Jesus is not what you get when you mix blue and yellow together and end up with green without change.

[Historian]

That means in assuming human flesh, the Logos did not cease to be what he had always been. There's no change of substance in the.

[Theologian]

Divine Son, without division. So the two natures do not represent a split in the Divine Person. Jesus is not half God, half man and without separation. So the union in the person is a real organic union, not simply a relational partnership. Chalcedon is extremely careful and necessary.

[Historian]

And all of that may sound very.

[Theologian]

Strange from the way the Bible talks. And yet it's defending what the Bible teaches, namely that the divine nature was united in the Person of the Son with a human nature, and the two natures are united in one only Divine person.

[Historian]

As Chalcedon puts it, the characteristics of each nature are preserved in no way annulled by the union, even as they come together in one person and one subsistence. All of this matters for us and for our salvation.

[Theologian]

We are not saved by two natures working together, but by one divine Person, the Lord Jesus Christ, consisting of a human nature and a divine nature.

[Kevin DeYoung]

You've been listening to Doctrine Matters with.

[Co-host]

Me, Kevin DeYoung, your host and teacher.

[Kevin DeYoung]

If you'd like to learn more about the topics we talked about today, you can check out my book Daily Doctrine.

[Co-host]

It's available in print or audio from.

[Kevin DeYoung]

Crossway.org and you may want to talk.

[Co-host]

To your pastor or a trusted friend who can recommend other good the Doctrine.

[Kevin DeYoung]

Matters podcast is produced by Crossway, a.

[Co-host]

Non profit ministry that exists solely for the purpose of proclaiming the truth of God's Word through publishing gospel centered content.

[Kevin DeYoung]

To learn more, visit Crossway.org until next week, I'm Kevin DeYoung and this has been Doctrine Matters.

[Co-host]

Thanks for joining us.