What Does It Mean That “God Became Man”?

Biblical and Historic Teaching of the Incarnation

The Bible teaches that Jesus Christ, the Word who was with God and was God, “became flesh and dwelt among us” (John 1:1-3, 14). We learn from Scripture that in Christ “all the fullness of God was pleased to dwell” (Colossians 1:19), that “he is the radiance of the glory of God and the exact imprint of His nature, and [that] he upholds the universe by the word of his power” (Hebrews 1:3). In short, we believe, based upon the biblical teaching, that Jesus Christ, “though he was in the form of God, did not count equality with God a thing to be grasped, but emptied himself, by taking the form of a servant, being born in the likeness of men. And being found in human form, he humbled himself by becoming obedient to the point of death, even death on a cross” (Philippians 2:6-8).

The church, propelled to clarify its witness by various false teachings about the nature of God and the nature of Christ, synthesized the biblical data and produced the ecumenical creeds. In the Nicene Creed the church confesses that “the Lord Jesus Christ, [is] the only-begotten Son of God . . . God of God, Light of light, very God of very God, begotten, not made . . . who for us men, and for our salvation, came down from heaven, and was incarnate by the Holy Ghost of the Virgin Mary, and was made man.”

And it is worth quoting the Athanasian Creed at length:

It is necessary to everlasting salvation that [we] also believe faithfully the incarnation of our Lord Jesus Christ. For the right faith is, that we believe and confess that our Lord Jesus Christ, the Son of God, is God and Man; God of the Substance of the Father, begotten before the worlds; and Man of the substance of His mother, born in the world; Perfect God and perfect Man, of a reasonable soul and human flesh subsisting. Equal to the Father as touching His Godhead, and inferior to the Father as touching His manhood; Who, although He be God and Man, yet He is not two, but one Christ: One, not by conversion of the Godhead into flesh, but by taking the manhood into God; One altogether; not by confusion of Substance, but by unity of Person. For as the reasonable soul and flesh is one man, so God and Man is one Christ.

This biblical and historic teaching has been well summarized by the Westminster Confession of Faith:

The Son of God, the second person in the Trinity, being very and eternal God, of one substance and equal with the Father, did, when the fullness of time was come, take upon him man’s nature, with all the essential properties, and common infirmities thereof, yet without sin; being conceived by the power of the Holy Ghost, in the womb of the virgin Mary, of her substance. So that two whole, perfect, and distinct natures, the Godhead and the manhood, were inseparably joined together in one person, without conversion, composition, or confusion. Which person is very God, and very man, yet one Christ, the only Mediator between God and man (8.2).

Speaking Faithfully of God the Son Incarnate

So, then, how should we speak faithfully of God the Son Incarnate? This question is partly the product of the biblical phraseologies that “the Word became flesh” (John 1:14) and that Christ “emptied himself” (Philippians 2:7), and partly the product of popular preaching which uses these phraseologies. In order to answer the question, we must break it down into two parts: 1) What does the Bible mean (and what do we mean) when it says that “the Word became flesh”/Christ “emptied himself,” and what does it not mean? 2) Based on what the Bible means by saying that “the Word became flesh”/Christ “emptied himself,” how should we rightly speak of the Word Incarnate? We’ll take the questions one-at-a-time.

1) It might be helpful to begin by saying what the Bible does not mean when it says that the Word became flesh. We know that the Bible does not, indeed cannot, mean that the Word ceased to be God when He became flesh. In the same verse which says that “the Word became flesh,” we read: “we have seen His glory, glory as of the only Son from the Father, full of grace and truth” (John 1:14). The fact that John says that he had seen the glory of the Son necessarily means that the Son is equal to God, even after He has become human, for only God the Son can have this glory from God the Father. That’s why John can say that “from His fullness we have all received, grace upon grace” (v. 16). Only God can bestow grace upon human beings, so the Word-become-flesh must still be God. This is then fully confirmed by John when he says, “No one has ever seen God; the only God, who is at the Father’s side, He has made Him known” (v. 18). Since only God can make God known, and since the Word-become-flesh makes God known, the Word-become-flesh must be God. So when we say that “the Word became flesh,” we do not mean that the Word became something intrinsically different than what He always was: the immutable God (cf. Malachi 3:6).

Even when Paul says that Christ Jesus “emptied himself,” he qualifies that by saying that Christ emptied himself “by taking the form of a servant” (Philippians 2:7, emphasis added). So Christ does not empty himself in the sense that he divests himself of his divinity, but in the sense that he unites humanity to his divinity without, as the Westminster Confession of Faith says, “conversion, composition, or confusion.” In other words, in the Incarnation, Christ does not cease to be God even as he takes on human flesh. So Christ is truly God and truly man, two natures in one person. This is where the words of the Athanasian Creed will help us: Jesus Christ is “one, not by conversion of the Godhead into flesh, but by taking the manhood into God; One altogether; not by confusion of Substance, but by unity of Person.” So Christ is one not because he ceased to be God when he became man, nor because his divinity fused together with his humanity to “create” one person with one nature; rather, Christ is one in that he is truly God and truly man, two natures united in one Person.

2) So how can we speak faithfully of this great mystery of the Incarnation? It is perhaps best here to say that whatever we do say about this great mystery, our words will inevitably fail to capture its full reality. While we can say something true of God becoming man by way of analogy, we cannot comprehend this unsearchable mystery in all its glory. We must proceed with caution when handling these divine matters: “How can the finite comprehend the infinite?”

Yet so that we are not resigned to complete silence, we venture forward carefully, in light of Scripture and the church’s reflection on the Incarnation, to provide a positive statement of this great mystery. While we cannot offer a full exploration of this doctrine now, nevertheless it will be helpful for us to learn of the Reformed doctrine of communicatio idiomatum, or the communication of properties. Simply put, the communicatio idiomatum refers to how our speech about one nature of Christ can be applied to the whole person, but not necessarily to the other nature. So what we can truly say about Christ’s humanity we can also truly say about Christ’s person, but that does not necessarily mean that we can say it of Christ’s divinity.

For example, we read in Scripture that “Jesus increased in wisdom and in stature and in favor with God and man” (Luke 2:52), but we also read that “Jesus Christ is the same yesterday and today and forever” (Hebrews 13:8). The communicatio idiomatum helps us hold these two truths together without contradiction: Luke is referring specifically to Jesus’ humanity whereas the author of Hebrews is referring specifically to Jesus’ divinity. So according to his humanity, Jesus grew in wisdom, stature, and favor, which means that we can say that Jesus himself grew in wisdom, stature, and favor. But also, according to his divinity, Jesus is the same yesterday, today, and forever, which means that we can say that Jesus himself is the same yesterday, today, and forever. While this is deeply mysterious, it is nevertheless not a contradiction since we are referring to Jesus’ two natures in order to establish what we can say concerning Jesus’ person.

When we speak of the Word becoming flesh, then, we must always remember that the Word did not cease to be God as He truly united human flesh to Himself. When we speak of the Son of God dying on the cross for sins, we must remember that we are technically referring to his humanity since in his divinity he is “immortal” (1 Timothy 6:16) and therefore cannot die. When we speak of God’s blood which obtained the church (cf. Acts 19:28), we must again be technically referring to Jesus’ humanity since “God is spirit” (John 4:24) and therefore does not have a body. Nevertheless, these realities are true of Jesus’ person even if not technically true of Jesus’ divinity, and therefore, in a technical sense, we can use them to speak faithfully about Jesus.

The point of using these apparently contradictory examples is to say that we must speak carefully and faithfully about God Incarnate. These careful and faithful words do not in any way diminish the mystery of God, as if we could do such a thing; rather, careful and faithful words actually preserve the mystery of God for us and point out how mysterious God truly is. It comes as no surprise that the God “who dwells in unapproachable light” (1 Timothy 6:16) is mysterious to us. Nevertheless, we must still speak carefully about Him and His revelation. If we are not careful, we are bound to overemphasize one aspect of that revelation, such as an overemphasis on Jesus’ humanity on the one hand or Jesus’ divinity on the other, and therefore fail to declare and teach “the whole counsel of God” (Acts 19:27).