The Incarnation and Two Natures of Christ

The question Jesus asked his disciples is still alive and well today: “Who do people say that I am?” (Mark 8:27). As in the first century, so today, there is much confusion regarding Jesus’ identity, even though everyone admits that Jesus is one of the most towering figures of history. The disciples responded to Jesus’ question by listing some of the diverse answers of their day, yet every answer only viewed Jesus in the category of a mere human. Today, similar to Jesus’ day, people continue to answer Jesus’ question with diverse and confused answers.

However, in total contrast to these views of Jesus, whether from the first century or today, Scripture, along with the Confessional standards of Nicaea (325) and Chalcedon (451), present a different answer to Jesus’ question. Who is Jesus? Jesus is the divine Son, the second person of the triune Godhead, the Lord of Glory, who in time assumed a human nature, so that now and forevermore he is the eternal “Word made flesh” (John 1:14). For this reason, Jesus is in a category all by himself as the unique, exclusive, and only Lord and Savior (John 14:6; Acts 4:12). This is also why confusion about Jesus’ identity is no small matter. There is nothing more important than knowing who Jesus is. This is not merely an academic debate, something for theologians to ponder; it’s a question vital for all people and especially for the church.

Let’s think through who Jesus is as God the Son incarnate from Scripture and confessional orthodoxy by unpacking five summary statements about him.

(1) Jesus is God the Son, the second person of the Trinity, who has eternally shared the one, undivided divine nature with the Father and Spirit and is thus fully God.

John makes this point when he reminds us that the “Word with God” (thus a distinct “person”) yet also “was God” (thus equal with God), thus underscoring the triune person-relations and a fully shared divine nature within God (John 1:1). Jesus, then, is the divine Son, and as the Son, he is not a created being. Instead, he is the eternal Son through whom all things were created and are now sustained (Col. 1:15-17; Heb. 1:1-3). It’s this Son, who became flesh (John 1:14) and by virtue of the incarnation and his work becomes our Redeemer and Lord.

The biblical evidence for the Son’s full deity is abundant. From the opening of the New Testament, Jesus is identified as Yahweh by inaugurating God’s kingdom—thus doing God’s work (Isa. 9:6-7; Jer. 31:31-34; Ezek. 34:1-31). This is why his miracles are not merely human acts empowered by the Spirit; rather, they are demonstrations of his own divine authority as the one who inaugurates God’s saving reign (Matt. 8:23-27; 14:22-23), rules over Satan (Matt. 12:27-28), and all things (Eph. 1:9-10; 19-23). With the Father and Spirit, the Son fully and equally shares the one divine name and nature (Matt. 28:18-20; John 8:58; Phil. 2:9-11; Col. 2:9). The Son is also identified as God (theos) (John 1:1, 18; 20:28; Rom. 9:5; Titus 2:13; Heb. 1:8; 2Pet. 1:1) because he is the exact image and correspondence of the Father (Col. 1:15; Heb. 1:3). As the Son, he inseparably shares with the Father and Spirit the divine rule, works, and receives divine worship (Psa. 110:1; Eph. 1:22; Phil. 2:9-11; Col. 1:15-20; Heb. 1:1-3; Rev. 5:11-12). This is why Jesus has authority to forgive sin (Mark 2:3-12), to say that all Scripture is fulfilled in him (Matt. 5:17-19), and to acknowledge that he is from the Father as the Son, but also equal to the Father as the divine Son (Matt. 11:25-27; John 5:16-30; 10:14-30; 14:9-13).

To account for what Scripture teaches about Jesus and his relation to the Father and Spirit, the Church distinguished between the person (or subject) of the incarnation, and the nature(s) the person subsisted in. The “person-nature” distinction was a theological distinction necessary to account for Scripture’s presentation of the one God who is triune. To explain all the biblical data, the Church distinguished the Father, Son, and Spirit without separating them into three Gods. Instead, Christian theology affirmed that there are three distinct divine “persons” who fully share the one, undivided divine “nature” and that the one divine nature wholly subsists in each of the three persons so that each person is fully and equally God (contra Arianism that denied Christ’s deity).

“Nature” (Gk: ousia; Latin: essentia, substantia), then, referred to what an object is. A divine nature is what God is in his one, undivided essence, which we describe in terms of God’s attributes. A human nature is what constitutes humanity, namely, a body-soul composite with corresponding capacities, such as a will, mind, and emotions. In Christ, there is one “person” (Gk: hypostasis; Latin: persona), the Son, who is the subject of two “natures” that subsists in both natures and acts through them. The “person” is the “acting subject”; natures are not. Yet, what is true of each nature is true of the one person (known as “communication of attributes”).

(2) Jesus is God the Son incarnate.

The word “incarnation” comes from the Latin (in + carnes [flesh]), which means “in the flesh.” Scripture teaches that the divine Son (person), who eternally shares the divine nature with the Father and Spirit, acted to assume a human nature without a human “person/subject” (contra Nestorianism that affirmed two “persons” in Christ). As a result, God the Son became incarnate.

It’s crucial to think of the incarnation as an act of addition, not subtraction, by the sovereign, effectual means of a virgin conception (Matt. 1:18-25; Luke 1:26-38). The Son, from the Father and by the supernatural and sanctifying agency of the Spirit, without change or loss of his deity, added a second nature to himself consisting of a human body and soul (John 1:14, Phil. 2:6-8). As a result, the Son permanently added a human dimension to his personal, divine life, and became present to us in a new mode of existence as the incarnate Son. The Son’s subsistence and action is now in both natures so that the Son is able to act in both natures and produce effects consistent and proper to each nature. Thus, as the incarnate Son, Jesus is able to render human obedience (Luke 2:52; 22:29-44; Heb. 5:8-10) for us as the last Adam (Heb. 2:5-18; Rom. 5:12-21), and to do a divine work by securing our eternal redemption (Eph. 1:7-10), and justifying us before God as covenant representative and substitute (Rom. 3:21-26; 4:25; 1Pet. 3:18).

The biblical evidence for Christ’s full humanity is also abundant. Jesus is presented as a Jewish man who was born, underwent the normal process of growth and development (Luke 2:52), who experienced a full range of human experiences (Matt. 8:10, 24; 9:36; Luke 22:44; John 19:28) including growth in knowledge (Mark 13:32), and the experience of death (John 19:30). Apart from his sinlessness, which Scripture clearly teaches (John 8:46; 2Cor. 5:21; Heb. 4:15; 1Pet. 1:19), Jesus is one with us in every way.

(3) The human nature assumed by the divine Son was unfallen and sinless.

Christ’s human body and soul had all the capacities of original humanity thus enabling the Son to be human and to live and experience a fully human life, against Docetism (Christ only appeared to be human) and Apollinarianism (Christ only assumed an incomplete human nature). Also, it’s best to think of Christ’s body and soul as unfallen and not tainted by the transmission or transgressions of sin. This affirmation is against the view that Christ assumed a fallen human nature while remaining sinless, which is problematic for a number of reasons.

First, a fallen incarnation lacks biblical support. Expressions such as “born in the likeness of men” (Phil. 2:7), “being found in human form” (Phil. 2:8), and “in the likeness of sinful flesh” (Rom. 8:3) refer to our common human nature, not our corrupt, fallen human nature. The object of the incarnation is always humanity, not sin. Christ came to represent a new humanity. We already have a representative of fallen humanity: the first Adam, in whose transgression we all sinned and came under the penalty of death (Rom. 5:12). Jesus is not “in Adam” as we are, and thus he is not fallen.

Second, a fallen incarnation seems to imply that corruption is essential to humanity since Christ cannot be like us unless he takes on a fallen human nature. No doubt, all humans now are fallen and live in an abnormal world, but it’s crucial to remember that this is an aberration of God’s original creation and glorification intent for us. Fallenness is not essential to us, and thankfully Christ was fully human yet sinless and unfallen, hence the reason why he is the head of the new creation (2Cor. 5:17), and the pattern of our glorified humanity (1Cor. 15:35-58).

Third, in the case of Christ, a fallen incarnation requires that we separate fallen from sinful and Christ’s person from the human nature he assumes. But this is difficult to warrant biblically and theologically. In Scripture, a fallen nature is the result of sin against God that places us in a state and condition of sinfulness under God’s judgment (Gen. 2:17; Rom. 5:12-21; 6:23; Eph. 2:1-3). But Christ is not “in Adam” like us, and the perfect Son does not assume anything fallen.

For these reasons, it’s better to affirm that Christ’s human nature was unfallen and sinless by the sovereign, sanctifying agency of the Spirit. Our inborn inclination to anti-God rebellion was not part of Jesus’ human makeup. Jesus was fully human and experienced the effects of living in a fallen world, but he did not share the guilt or disposition of Adam’s sin passed on to us. Jesus never committed a sin, nor could he (Matt. 3:15; John 8:46; Heb. 4:15; 7:26; 1Pet. 1:19). He was tempted like us, but he perfectly obeyed his Father, even unto death, as our covenant mediator, thus accomplishing our salvation as the man Christ Jesus (1Tim. 2:5; Heb. 5:5-10).

But if Jesus could not sin (i.e., impeccable), were his temptations genuine? Although Jesus did not sin, how is he like us if he was not able to sin? To answer this important question, we need to remember the following points.

First, Jesus was genuinely tempted yet “without sin” (Heb. 4:15). As the obedient Son, from the beginning of his ministry to the cross, he faced temptations and sufferings for us (Luke 4:1-13; 22:39-46). Yet this does not entail that his temptations were identical to ours in every respect. Why? Because although Jesus is fully human, he is also the divine Son and his temptations reflect this fact. For example, Jesus was tempted to turn rocks into bread (not something we are tempted with) thus using his divine power instead of obeying his Father’s will to render human obedience for us (Heb. 2:5-18; 5:8-10; cf. Rom. 5:12-21). Also, unlike us, Jesus was not tempted by anything internal to himself. He was not enticed by sinful desires contrary to God’s creational and moral norms since there was no sin in him, not even a predisposition to sin, given the sanctifying work of the Spirit. Instead, Jesus was tempted by normal sinless human weaknesses and external forces. He was tempted by hunger, fear of pain, and his own holy affections. Foremost among these desires was his perfect fellowship with his Father, which he wrestled with in Gethsemane. In fact, we can say that Jesus’ temptations were not only genuine; they were more real than we could ever imagine or experience since he never yielded to temptation as we do. He unswervingly and joyfully obeyed his Father’s will at great cost for our salvation.

Second, Jesus is impeccable because he is the divine Son who assumed a human nature, and as such, his human nature never existed apart from its union in the Son (i.e., hypostatic union). Jesus is not merely another Adam; he is the head of the new creation, the eternal Son incarnate. And as the Son, it’s impossible for him to sin and to yield to temptation because God cannot sin. In fact, it’s this truth that grounds our assurance that God’s plan cannot fail and why the last Adam is greater than the first.

Third, although Jesus is impeccable due to his divine person, it’s also true that he, as our covenant representative, had to render human obedience for us. The Son’s action in and through his human nature did not change the integrity of the nature; he lived, acted, and faced every temptation as a true man to redeem us. And as Scripture wonderful reminds us, it’s for this reason that Jesus not only secured our eternal salvation but also became our sympathetic Savior (Heb. 2:18; 4:14-16). Also, we must emphasize the Spirit’s work on Christ’s human nature. Jesus is impeccable because he is the eternal Son who subsists and acts in both natures, but Jesus did not sin because of his reliance on the Spirit at work in him. From conception, the Spirit sanctified, gifted, and empowered Jesus in his humanity so that he obeyed for us as a man.

All of this entails that Jesus’ temptations were genuine although he could not sin. As the sinless one who could not sin, he still had to choose to forgo his rights and privileges for us, even to death on a cross (Phil. 2:8; Heb. 12:2-3). But by doing so, he perfectly fulfilled the Father’s will by the Spirit, secured our redemption, and in his humanity became the pattern of our glorified humanity (1Cor. 15:45-49).

(4) As a result of the incarnation, the divine Son now subsists and acts in two natures without changing the integrity of either nature, confusing them, or making them a hybrid of divine and human. Yet, the Son was not limited to acting through his human nature alone since he continued to act through his divine nature as he has from eternity.

In and through his human nature, the Son lives and acts within the normal physical, mental, volitional, and psychological capacities of an unfallen, sinless human nature. As the Son, he experienced the wonder and weaknesses of a human life. He grew physically and mentally (Luke 2:52), experienced tears and joy, and suffered death and a glorious resurrection for his people and their salvation (John 11:33, 35; 19:30; 1Cor. 15:3-4).

However, the same Son who experienced these things as a man also continues to live and act as he has done from eternity as God the Son in relation with the Father and Spirit. This truth is taught in Scripture’s affirmation that the incarnate Son continues to uphold the universe (Col. 1:16-17; Heb. 1:3), alongside Christ’s other divine actions during his life and ministry. In Christ, his two natures remain distinct and retain their own attributes and integrity (against Monophysitism that blended Christ’s two natures), yet he is able to act through both natures. The Son, then, is not completely “limited” by his human nature; he is also able to act “outside” (extra) of it in his divine nature as he has always done. The Son, who has always inseparably acted from the Father and by the Spirit, continues to do so. But now, due to the incarnation, he acts through both natures without changing or diminishing either nature.

(5) By the incarnation, our Lord Jesus Christ became the first man of the new creation, our glorious mediator and new covenant head.

By his incarnation and work, Jesus, God the Son incarnate, has reversed the work of the first man and became our Lord and Savior (Rom. 1:3-4; Heb. 2:10). He has become perfectly qualified to meet our every need, especially our need for the forgiveness of sin (Jer. 31:34; Heb. 7:22-28; 9:15-10:18). Given who God is, it’s only the incarnate Son who can redeem us by doing a divine-human work as our Redeemer. As the divine Son, he alone satisfies his own judgment on sinful humanity and demand for perfect obedience (Rom. 5:12-21). As the incarnate Son, he alone identifies with us as our representative and substitute (Heb. 5:1). Our salvation hope for the payment of our sin and our full restoration as God’s image-bearers is only accomplished by Christ alone (Rom. 3:21-26; Heb. 2:5-18). As a result, our Lord Jesus Christ rightly demands and deserves our faith, love, and obedience.