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Why Did God Become Man? – Dr. Stephen Wellum

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Dr. Arnold interviews Dr. Stephen Wellum (Professor of Christian Theology at Southern Seminary) about the Bible’s teaching that Christ is both God and man and yet remains one person. This amazing mystery is called the doctrine of the incarnation.

Conversation topics include:

  • What does it mean to say that Christ has two natures, yet remains one person?
  • What does it mean when we read in Philippians 2:7 that Christ “emptied” himself? Did Jesus surrender his divinity in becoming human?
  • How we have no salvation without a divine and human Redeemer.
  • An early Christian creed that affirms this doctrine.



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Introduction (00:01):

Welcome to Faith Seeking Understanding a podcast from Phoenix Seminary, helping Christians grow in their understanding of the faith, hosted by Dr. Brian Arnold, president of Phoenix Seminary.

Brian Arnold (00:16):

Jesus Christ is at the center of the Christian faith. To be a Christian is to be a follower of Christ, and so understanding this God-man should be the highest priority we have as being disciples of Christ. With us today is Dr. Stephen Wellum. Dr. Wellum holds a PhD from Trinity Evangelical Seminary, and he’s taught at The Southern Baptist Theological Seminary since 1999. He’s written several books, including my all-time favorite book on the person of Christ, called God the Son Incarnate, published just a few years ago with Crossway. Dr. Wellum, thanks for joining us today.

Stephen Wellum (00:50):

Oh, I’m glad to be with you. Thank you for having me.

Brian Arnold (00:52):

The mystery of God made man is the cornerstone, as I said, of the Christian faith. And yet it seems to be the most difficult of all the doctrines to understand. I’m a church historian, and I study especially second and third century Christianity. One of the church fathers named Tertullian from Carthage famously said “credo quia absurdum est,” which means “I believe because it’s absurd.” And that is, that God would become man almost seems so absurd that it’s believable. So our big question that we’re going to be going over today is—why did God become man? So first, I think it’s fitting for us to even consider what we’re talking about with the God-man. So Dr. Wellum, what is the best way for Christians to understand how the eternal Son of God became Jesus of Nazareth?

Stephen Wellum (01:39):

Yeah, I mean, I think we go to a place like in John 1, the opening verses, so that…in the opening verse, it says “in the beginning was the Word” and “Word,” of course, in John’s Gospel, would be another name for the Son of God. So “in the beginning was the Word, the Word was with God and the Word was God.” So we see here—we don’t have a mention of the Holy Spirit—but we see the Trinitarian relations, that within God there are three persons: Father, Son, and Holy Spirit. The Word, who is the Son, is with God—that would be a reference to the Father—but is God. So is fully God. So that the second person of the Godhead, the Word or the Son—and then you go to John 1:14—became flesh. So that the Son, who is eternally God, has added to himself a human nature—and we will then speak about what a human nature is—he has added that to himself, so that the eternal Son of God, who is fully God, is now also fully human. And that’s really at the heart of the nature of the incarnation.

Brian Arnold (02:51):

That’s really helpful to understand, even thinking that God took on the human nature. I want to go for a deep dive question actually pretty quickly, and ask—does that change then the nature of God? If God is unchangeable, and yet he takes on a nature, does that actually change the nature of God?

Stephen Wellum (03:10):

Well, you know, we would say “no,” because God cannot change, in himself. So what’s going on? And it’s very important to see in that John text, which is crucial is…notice that it speaks in John 1:14 of the Word becoming flesh, or the Word adding to himself a human nature. It’s not the divine nature that adds a nature, right? Yes, the Son is fully God and shares the divine nature, but it’s what we call in the language of theology, the person of the Son. The person of the Son adds to himself a human nature, so that there are now two natures—two natures that remain in the sense of what we call the creator-creature distinction. At the heart of the Bible is: God is God, and humans, as creatures, are something of a different nature. So that the Son of God, the person, adds to himself a human nature, but it doesn’t change the divine nature. The divine nature isn’t adding a nature, it’s the person who’s adding the nature, so that the Son remains always what he has always, always been, but is now able, through that human nature, to live a human life, and to act as a human, and to become our Savior, and to obey, and to die for us, and to be raised for us—yet there’s two natures in Christ. If there was a blend of natures—somehow the creator-creature distinction was overcome—then of course you would have change in God, but that’s not what’s going on.

Brian Arnold (04:39):

Which is one of the errors that the early church made, was seeing this kind of “new nature” being formed of a blending between the man-nature and the God-nature.

Stephen Wellum (04:51):

Yeah, I mean, that was…it was famously tied to a man named Eutychius, and it was famously known as mono—one—physitism, which meant one nature. Right? And he saw that in the incarnation, when the Word became flesh, there was a kind of blend of natures. That was one view that the church says, no, no, no, no, no—God is God, and humans are humans. So that for the Son of God to become human, the person of the Son adds to himself a human nature, but does not compromise the divine nature. So that’s why we affirm, with the history of the church, there’s two natures: Jesus of Nazareth, as an individual, is the eternal Son—God the Son, who is fully God—but he has now a second nature. One person, two natures.

Brian Arnold (05:42):

That’s right. So adding on that nature of being a man, but not detracting away from his divinity. So what do we do with a passage of Scripture, like Philippians 2, where Paul says that “he emptied himself”—talking about Jesus—he “emptied himself.” And I even know of some pretty big church movements today where they go to a passage like this, and teach that Jesus somehow emptied himself of his divinity. So what do you say to somebody who would argue something like that? And what’s at stake in that question?

Stephen Wellum (06:15):

Well, I mean, everything’s at stake, right? I mean, the deity of the Son, who Jesus is from the entire Bible, and ultimately salvation is at stake, because we would not have the kind of Redeemer that we need: one who is both fully God and fully human. But Philippians 2 a is a text that just simply does not teach that kind of viewpoint, because as you walk through Philippians 2—and it’s a glorious passage, I mean, Philippians 2:6-11—you start with “he who is in,” speaking about Christ Jesus, “he, who is in very form”—or well-translated “nature”—”of the very nature, God.” So that here Paul is starting off very clearly that he is fully God, right? He’s in the very nature of God, “did not consider that to be sort of clung on to.” But instead, and there’s a lot of sort of phrases in there that have to be carefully translated.

Stephen Wellum (07:11):

But I think it would say “he made himself a nobody.” But how did he make himself a nobody by emptying? The idea of emptying is really a metaphor for “made himself a nobody.” He “emptied” himself. And the text is very clear in the next two phrases, is that he added something to himself. So he made himself, or he emptied himself by adding to himself, the very same word used, “form, or nature, of a servant being found in human likeness.” So the two phrases define what it means to empty. And the definition of emptying is addition. So it’s very, very important to see that in the incarnation, when the Word becomes flesh, he is not subtracting deity. He’s not emptying deity. The “emptying” is defined by the addition of a human nature. Now, what that entails, why that’s emptying, is that the Son of God, in and through that human nature, now lives a full human life.

Stephen Wellum (08:11):

He’s fully human. He knows what it means…you think of Luke 2, where he grows in wisdom, stature, favor with God and man, in terms of that human nature. He knows what it means to be in that human nature in a womb, to be born, to go through growth in life, to experience all that we experience—that is humbling. And then the apostle Paul will say, there’s even a further humbling to death on a cross. And he’s able to do that in and through his humanity. He can only die because he has a human nature. So Philippians 2 is very, very clear. He who is eternally God, adds to himself incarnation as addition, not subtraction. And this is born out in many other passages. You have some who will say the emptying is the surrendering of the divine nature.

Stephen Wellum (09:00):

That’s a very extreme view. And that is not what the text is saying. And of course you would not have the deity of Christ anymore. You would not have the Trinity. Others will say, well, he sets aside certain divine attributes. Well, that makes no sense at all, because God doesn’t set aside attributes. That wouldn’t be divine, that wouldn’t be God anymore. There’d be change, and so on in God—the Trinitarian relations would all change. Or others will then say, more at the popular level, he chooses not to exercise the function of those divine attributes. The problem with that is yes, when he’s acting through his humanity, he doesn’t make the human nature deity. Yet you do have to do justice to, say a Colossians 1:17, where the incarnate Son, the Son of God, the Lord Jesus, is the one who sustains the universe.

Stephen Wellum (09:53):

And the emphasis in that text is, he’s not only sustained the universe since its creation, where he is the Creator of it, but he continues to sustain it. Well, that is a divine act. He does not do that in his human nature. He does that as he has always done, in relation to the Father and Spirit, through the divine nature. So that even as the incarnate one, he continues to exercise divine attributes through his deity. Not through his humanity, but through his deity. So you cannot then say that he’s setting aside even the use of those attributes, or the divine nature. Philippians 2 doesn’t teach it, and other passages don’t teach it as well.

Brian Arnold (10:36):

And it helps us understand how the divinity can still be active in Jesus, who’s in a particular locale, a certain place in space and time, in his incarnation. And theologians have used the phrase, the extra Calvinisticum, to explain this phenomenon. How would you describe that?

Stephen Wellum (10:56):

Yeah, that’s a very, very important concept that unfortunately, you know, in most of our evangelical churches, and I must say, even in my seminary education where—you know, I went to a very, very good seminary—I never heard about it. But this is part of the entire history of the tradition of the church. And it’s also biblical, in terms of say, Colossians 1:17. The extra, and sometimes it’s associated with Calvin as you have done, but really if we just call it the extra—extra simply means “outside of.” And so the emphasis here is that in the incarnation the Son of God takes on a human nature. So he has two natures, and he is able to act simultaneously through both natures. Now, when he acts in the human nature, he’s acting as a human. He’s not exercising divine attributes, but he is able to also act as he’s always done—through his divine nature.

Stephen Wellum (11:50):

So that in the incarnation, the Son is able to act outside of—he is not limited to—merely the human nature. He still continues in Trinitarian relation with the Father and the Spirit to sustain the universe, to act in terms of his deity. “Outside of” is outside of the human nature. Now, there are many who then say the “emptying” means that he, the Son of God in the incarnation, only acts through his human nature. Well he does act through his human nature, but he’s not limited to it. He’s also able to act outside of it. And that’s what the extra is getting at.

Brian Arnold (12:26):

Absolutely. And I’m happy you circled back around, because in that Philippians 2 passage, the word used for “empty” is kenosis. This is where we get this idea of kenotic Christology, where Jesus does empty himself somehow of his divinity. And I see a resurgence of this happening. Why do you think that is? Why are people attracted to some sort of a kenosis theory of Christology?

Stephen Wellum (12:48):

Well, there’s probably a lot of reasons. I mean, I think one is just theology is not being taught, right? So that, you know, we’re having…even when we’re having exposition of Scripture, it’s not being tied to sound theological thinking, and putting all of Scripture together in all that it says. I think also we do live in a time period where, you know, so much on the humanity of Christ and his identification with us and so on is emphasized, that something of his Lordship and his deity is undermined. And it may be some cultural influences that are coming in there. I mean, we know with the latest state of theology poll that was put out by Ligonier ministries and Lifeway, that some of the questions there regarding Christ are shocking. To see that those who affirm evangelical beliefs, 30% of them are saying Jesus is merely a human teacher, not God. Not God, the Son. Or when they’re asked about Jesus being the first and greatest created being, which is really what the early Arians held to, or modern day Jehovah’s Witnesses, you know, 65% are affirming that.

Stephen Wellum (14:00):

So I think we have an incredible amount of biblical…lack of biblical knowledge. I think we have a lack of theological knowledge, and I think there’s cultural pushes to make Jesus just simply another human who identifies with us, sympathize with us, but his Lordship is lost. And I think these are all factors for, you know, the appeal of this kind of kenotic view.

Brian Arnold (14:23):

Yeah, I think you’re right. And those reports are terrifying. The Ligonier one, you mentioned about how, you know, 70% of Christians or so, hold a wrong view of who Jesus is. And I really appreciate that less-than-subtle plug for Phoenix Seminary. It’s a great place to come and study and to learn these things, so that people can be equipped when they go out into ministry and teach these things appropriately. So let’s get back then to our big major question, which is—why did God become man, which is kind of the “so what?” question of the incarnation.

Stephen Wellum (14:52):

Well, I mean, the answer…you know, the large answer is that God became man, and God the Son became flesh—the Word became flesh—in order to glorify God, to glorify himself, in the salvation of a people, right? So, I mean, it’s…God is bringing glory to himself. He’s not doing the incarnation simply for, you know, just learning what’s going on on earth. It’s to…ultimately for his self glorification, through the creation and redemption of a people. And so that’s the larger issue. And then you have a passage such as a Hebrews 2, for instance, verses five through 18, which nicely gives—it’s not all that could be said—but it nicely gives really the answer to this question. You know, why did the Son of God become human? Why did he take on our humanity?

Stephen Wellum (15:43):

Well, he did so for our salvation. And in the context of Hebrews 2, the author quotes Psalm 8 and then identifies Christ as “last Adam.” So Christ, the Son of God becomes human in order to restore what Adam lost. He takes on our humanity, so that he’s able to identify with us, and represent us, and be our substitute for us, in order to save us, and redeem us, and restore us. He does this to ultimately defeat all of the effects of sin and death. And that’s described in Hebrews 2:14 and so on, as the defeat of our enemies—sin, and death, and the devil. And ultimately the reason is to reconcile us to God. It’s that we stand as sinners before God; we stand under his judgment. We are guilty before him, and we need a Redeemer—we need God and one who is human—to justify us before God: to represent us, to identify with us, and to pay for our sin. I mean, those are the ultimate reasons for the incarnation, which then leads to a new heavens and new earth. So God’s self-glorification in redemption of a people. And this is the only way that he can redeem us is through his incarnate Son and his entire work for us.

Brian Arnold (17:01):

And as you said, you know, “why did God become man?” really boils down to a question of salvation. If God didn’t become man, we could not be saved from our sins. So maybe walk us through—if Jesus wasn’t fully human or he wasn’t fully divine, why is it that we could not be saved?

Stephen Wellum (17:19):

Well, I mean it’s a crucial question and, you know, at the heart of the gospel, right? So if we take, I think just the humanity side of it first, right? So we have to think carefully through the Bible’s storyline, it’s covenantal structures, the importance of humans in God’s plan, and so on. So we go back to creation and we see the role of Adam. We see him as image and likeness. All of us humans are made in the image of God. And Adam is our covenant head and representative. We are to rule over the world. He is to obey God, but he disobeys, so that we need—and of course, this is tied to the promise of Genesis 3:15—God has promised that another Adam will obey for us, that he will reverse the effects of sin and death.

Stephen Wellum (18:10):

And so we learn from that, that in order to redeem us, we need one who is human, who identifies with us, who is able to represent us, who is able to do what Adam didn’t do, namely perfectly obey God’s will and to keep all of God’s demands that he placed upon him. And so there’s the human aspect. We need one to be human, who will represent us, who will obey for us, who will be the perfect covenant keeper. And of course, that is a strong emphasis on the reason for the incarnation. And Jesus comes and is obedient, even to death on a cross as our representative and substitute. But we have to say more than that, right? Because at the heart of Adam’s sin, and the whole human race, is that we’ve sinned before God. And sinning before God, we then have to define very carefully, the biblical understanding of God.

Stephen Wellum (19:07):

God is triune. God is Holy. God is just. God is…a term for it is, he’s independent, self-sufficient. God is not only existent from himself—he needs nothing—God is the source and standard of truth, right? He doesn’t look outside of him to learn things. And in the moral realm, right, God is good. God is Holy. God is just. God is the moral standard of the universe. And when we sin against him, God doesn’t just sort of overlook our sin. He doesn’t just say, “well, let bygones be bygones.” Ultimately, he must uphold his own moral demand. Otherwise, he would not be God. And this provides, really, the rationale, at its heart, of why we need a divine Redeemer. We’ve sinned before God, and God, to forgive us, must ultimately satisfy his own demand against our sin. We could not satisfy that demand. And so in Christ, we have God taking his own demand.

Stephen Wellum (20:08):

God the Son, taking his own demand, paying for our sins in full—that’s what we call penal substitution. And he does so as our covenant representative, who obeys for us, who puts all things under his feet. And then, as a result of that, we are justified before God. We are restored by the work of the Spirit, united to Christ—to the purpose of our creation—to rule, to be transformed. I mean, that is why we need a divine and human Redeemer. And apart from that, we have no salvation the way the Bible describes it.

Brian Arnold (20:44):

Dr. Wellum, that has to be one of the most compelling demonstrations of the gospel I’ve heard in a long time, of just showing how important Jesus Christ, second person in the divine Trinity, is—to be that God-man, to rescue us from sin, and how it must have been that way. I know my heart is burning with passion for Christ right now, as I hope our listeners are too. What are some resources that you would point people to, maybe from the whole spectrum—things that they can just get their toes in the water, if they’ve never read anything on Christology, to something that’s a bit thicker for a more interested student.

Stephen Wellum (21:18):

Yeah. I mean, there’s some excellent, you know…you have historical works. I mean, if you wanted to go back even into the history of the church, Athanasius’s On the Incarnation, you know, a classic treatment. You know, more difficult work in the middle ages where you have Anselm writing Why God Became Man? I mean, he’s taking that question…that’s a difficult read, but, you know, is addressing those issues. Most of your historic theologies, to me, whether it’s Calvin’s Institutes and so on, their Christology section and reading that. I’ve tried to address it obviously, at a contemporary level, in God the Son Incarnate. And I have a new book, a shortened version of Short Studies with Crossway in Christology, coming out in February. So that will fit, you know, sort of just a quick read, a summary, trying to capture the biblical, and historical, and theological data. Donald Macleod has a very good book on the person of Christ. So excellent resources and practical works. Michael Reeves has another excellent book on Christology, the person of Christ as well. So those are some resources, both from history and contemporary.


Brian Arnold (22:27):

I think those are all fantastic options, especially encouraging people to go back and read some of the sources themselves. It makes me think of C.S. Lewis’s introduction to Athanasius’s On the Incarnation, telling people these are really accessible works. They’re not very long. And they really set the tone of the church’s trajectory on this issue of Christology, that we’ve held to for the last 1700 years. And I want to actually end us today in a little bit different of a way—to look back on the tradition, and what has been called the Chalcedonian definition, which was written in 451 at a church council, that is about a paragraph of summary of who the Lord Jesus Christ is. And it reads this way: “Therefore following the holy Fathers, we all with one accord, teach men to acknowledge one and the same Son, our Lord Jesus Christ, at once complete in Godhead and complete in manhood, truly God and truly man, consisting also of a reasonable soul and body; of one substance with the Father as regards his Godhead,

Brian Arnold (23:33):

and at the same time of one substance with us as regard to his manhood; like us in all respects, apart from sin; as regard to his 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; one and the same Christ, Son, Lord, Only-be gotten, recognized in two natures, without confusion, without change, without division, without separation; the distinction of natures being in no way anulled by the union, but rather the characteristics of each nature being preserved and coming together to form one person in subsistence, not as parted or separated into two persons, but one and the same Son and Only-begotten God the Word, Lord Jesus Christ; even as the prophets from the earliest times spoke of him and our Lord Jesus Christ himself taught us, and the creed of the Fathers has handed down to us.” That is what the church universal has held since 451. And Dr. Wellum, I thought you did a great job of helping us understand the God-man, Jesus Christ, and why he came to save us from our sins as has been taught even in this historical definition. So, Dr. Wellum, thank you so much for joining us today on Faith Seeking Understanding.

Stephen Wellum (24:58):

Well, it’s been my delight. Thank you very much for having me.

Outro (25:01):

Thank you for listening to the Faith Seeking Understanding podcast. If you want to grow more in your understanding of the faith, consider studying at Phoenix Seminary, where men and women are trained for Christ-centered ministry for the building up of healthy churches in Phoenix and throughout the world. Learn more at

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