Lesson One
Lesson Two
Lesson Three
Lesson Four
Lesson Five
Lesson Six
2 Activities | 1 Assessment
Lesson Seven
2 Activities | 1 Assessment
Lesson Eight
The Church
2 Activities | 1 Assessment
Lesson Nine
Humanity and Sin
2 Activities | 1 Assessment
Lesson Ten
The Work of Christ
2 Activities | 1 Assessment
Lesson Eleven
The Person of Christ
2 Activities | 1 Assessment
Lesson Twelve
The Holy Spirit
2 Activities | 1 Assessment
Lesson Thirteen
2 Activities | 1 Assessment
Lesson Fourteen
Last Things
2 Activities | 1 Assessment
Lesson Fifteen
Theology Today
1 Activity | 1 Assessment
Course Wrap-Up
Course Completion
1 Activity | 1 Assessment


God is Lord, not apart from servant humility, not in keeping distance from self-sacrifice and even death, but in the act of being a servant and dying on the cross. In this event, God says a definitive “no!” to human sin. He passes a verdict against the self-rule in which we would live by taking up that sin, by the Son becoming the sin that He did not know, and putting it to death. In turn, death itself, the consequence of sin, is undone. Hope for new life is brought about by God’s refusal of human disobedience and pride in Christ Jesus.

For this to be true, however, for the work of Christ to be effective in this way, it is necessary that Christ Himself be both the eternally electing God and the temporally elected human. It is necessary for Christ to participate in the lordship of God’s self-election and in the servanthood of being elected: that as God He says “no!” to human rebellion, and that as man He receives that “no!” on behalf of all humankind. For the work of Christ to make sense, the person of Christ must be uniquely comprised of two natures. He must be fully divine and fully human.

The second major area of christological dogma is the incarnation of the Son of God. Incarnation derives from the Latin root carnis, which means “flesh.” The incarnation refers to the “enfleshing” of the Son or, more fully, the teaching that in assuming the specific flesh of Jesus of Nazareth, the Son of God becomes human without forfeiting His Deity.

This dialectic between full Deity and full humanity is essential. You may have heard of the concept of incarnation in other religious traditions. The Hindu “avatar” is a popular example. What distinguishes the Christian teaching from similar teachings is its refusal to lose the divinity of the Word in the humanity of Jesus, or the humanity of Jesus in the divinity of the Word. Biblical faith confesses both without compromise.

Scripture’s testimony to the humanity of Christ begins in Old Testament prophecy. Two Messianic titles foster expectation of a human leader. Son of Man (ben adam), which might just as well be translated “a human one,” is a favorite appellation of Ezekiel, appearing more than 90 times in that book. There the title refers both to the prophet himself (e.g., 3:1; 4:1; 5:1; 6:1; 7:1) and to the object of his prophecy (e.g., 8:2ff.), who will bring judgment to Israel and restore justice in the land.

The justly ruling Son of Man is not of any human descent, but of the ancestry of King David. He is the Son of David (ben david). It is David whom God promises enduring offspring, a house that will continue forever and a line of kings that will persist (2 Sam. 7). Thus it is important for New Testament authors to demonstrate that Jesus was of “the house and line of David” (Luke 2:4).

Yet Old Testament messianic expectation included the idea that God’s anointed ruler would reign with insight and power beyond mere human capabilities. He would exercise qualities consistent with the attributes and will of YHWH. He would bear the very presence of God to His people, and, indeed, being established by God would rightly be called “Son of God.” Psalm 2:7 says of the King installed on Zion, “You are my Son; today I have become your Father.”

The New Testament witness to Christ picks up all three titles and applies them to Jesus. For example, Jesus is referred to as the Son of Man in Luke 9:58; 18:8; and 19:10; the Son of David in Matthew 1:1; Luke 18:38-39; and the Son of God in Matthew 16:16; John 1:14; 3:16, 18. Perhaps the most telling use of messianic titles takes place in Mark’s gospel.

This text is divided nearly in half between a presentation of Jesus as the powerful and authoritative “Son of God” (1:1–8:30) and the suffering “Son of Man” (8:31–16:8). In the first half of his gospel, Mark narrates stories that show Jesus doing what is expected of God—healing the sick, raising the dead, and, above all, forgiving sins. In the second half, Jesus predicts His rejection, teaches of His suffering, and is crucified. He is genuinely human.

Mark’s functional depiction of Christ as doing both what God does and subject to human limitations is reflected in the early church’s reasoning about Christ, as we will see momentarily. The apostles bore witness to what they encountered: On one hand they testified to a man who got tired and slept in a boat on the Sea of Galilee, who wept at Lazarus’ tomb, who cried out in anguish on Calvary and succumbed to death, and on the other hand they proclaimed one who forgave the sins of a paralyzed man and immoral woman, who raised His friend Lazarus and the synagogue ruler’s daughter from the dead, and who was raised from the tomb Himself on the third day. Thus they found in Jesus one

“who as to his human nature was a descendant of David, and who through the Spirit of holiness was declared with power to be the Son of God by his resurrection from the dead,”

Paul taught in Romans 1:3.

The Bible clearly teaches that Jesus acted with both human and divine characteristics, and merited the full range of messianic titles. Not as clear is the question as to whether Jesus was essentially divine acting as a human, or essentially human but endowed with divine powers, or essentially human and divine at once. And if the latter, what is the relationship between Christ’s humanity and divinity? Does His humanity necessarily limit His divinity, because He could not really be human and empathize with us if it did not? Or does His deity overpower His humanity, because He could not really be God and forgive sin if it did not? These are the questions that the early church had to answer, which answers we must think through again in order to determine how far they can be our own.

In Lecture Seven, we noted that the doctrine of the Trinity did not appear whole cloth out of heaven, but emerged through debate concerning Jesus’ divinity (and, as we will discuss next time, a parallel debate about the Spirit). Spearheading the debate was a presbyter or elder in the Alexandrian church named Arius (c. 250–c. 336). Arius is reported to have been intelligent, charismatic, deeply religious, and an eloquent preacher (cf., e.g., Latourette). We know that his views garnered a large following and endured for centuries after his death. Arianism, as his school of thought became known, involves several important dimensions, but the most significant is the teaching that the Son of God is not coeternal and therefore coequal with God the Father.

Much of what we know of Arius’ position is reconstructed by citation of his views in the writings of his opponents, always a dicey historical source. A few of Arius’ works have survived, however, including an important letter written in the early 320s, which contains some instructive language concerning what he actually believed. Explaining why he and his followers were being persecuted by other leaders in the church, Arius states that, “We say, ‘the Son has a beginning, but God is without beginning.’ ”

For Arius, there are two problems with contending that the Son of God is without beginning as the Father. First, it would place another entity alongside the Father, who is complete and perfect in Himself and thus, by definition, eternally singular. Secondly, it would suggest that God can somehow change, that He could be begotten or “originated.” But God is “unoriginate,” at least according to the standard account of God in the ancient Greco-Roman world.

Arius reflects a philosophical, specifically Platonic, concept of deity. According to Greek philosophy, God is immutable. “Immutable” means unable to change. Simply put, God cannot change. He is the fullness of being, unable to be more or otherwise than He is, and thus absolutely the same from all eternity. He does not become; he is, and this in a thoroughly static way. The problem is that Arius carried through these basic axioms so thoroughly that he could not help but understand the Son as something different than the Father. To differentiate the Son from the Father, he taught that unlike the Father, the Son had a beginning. He apparently interpreted “only begotten” (monogenes) in John 1:18 by emphasizing the generative connotation of the term, as if the Son was birthed.

It is important to recognize that Arius did not believe the Son, being begotten, is a creature just as we are. He took Christ to be the firstborn of God’s creatures chronologically and ontologically, that is, the Son enjoys a nature that is prior to and purer than ours, which are much farther down the line and, indeed, contingent upon him.

Christ’s is a nature capable of being the vehicle through which the Father created us; in fact, Arius felt that, though not divine, the Son did enjoy a kind of super-nature. But if Jesus is neither of the Father’s essence nor of human essence, then what is He? “We say [the Son] is from what is not,” Arius also wrote in the letter just mentioned. The Son originates from neither divinity nor humanity. Arius was forced into this peculiarly negative expression, because he had no means of accounting for the Son’s essence since He existed before humankind as the medium of God’s creative activity, yet not as God. His being is therefore somewhere in-between deity and humanity, something like a demigod, though Arius is basically unable to say much positive about the Son’s being.

Arianism is considered a type of subordinationism. This means that Arius and his followers subordinated Christ to God with respect to their natures. The church will ultimately reject this way of thinking about the Son of God, and in so doing it will remind us of our rule that while theology may make free use of philosophical constructs, it cannot be beholden to them, but must answer to the biblical data above all.

Arius’ chief opponent also haled from Alexandria. Athanasius (c. 296–373) was more than 40 years Arius’ junior. But he showed keen interest and ability in ecclesial matters from a young age and, as the Arian controversy was reaching an early crescendo in the 320s, Athanasius was already a deacon in the Alexandrian church. By 328, he would become bishop.

In contrast to the negative construal of Arius—neither fully God nor fully human —Athanasius argued that Christ is both human and divine, fully both. He came to this conclusion by reasoning that God, by His power as God, became a real human being in Jesus of Nazareth, and operated out of both divine and human provenances. “As God he raised the dead, healed all by a word, and also changed water into wine,” Athanasius wrote. “As a human being, he felt thirst and tiredness, and he suffered pain.” In Christ, both divinity and humanity are present and operative. Athanasius did not teach that Christ was sometimes human and sometimes divine or that He operated occasionally out of His humanity and occasionally out of His divinity. Rather, His activities . . .

All occurred in such a way that they were joined together; and the Lord, who marvelously performed those acts by his grace, was one. He spat in human fashion; but his spittle had divine power, for by it he restored sight to the eyes of the man blind from birth. When he willed to make himself known as God, he used his human tongue to signify this, when he said, “I and the Father are one.” He cured by his mere will. Yet it was by extending his human hand that he raised Peter’s mother-in-law when she had a fever, and raised from the dead the daughter of the ruler of the synagogue.

For Athanasius, there are two natures fully operative in Christ but working in complete harmony and unison. There are not two Christs; nor is there a split personality stemming from split natures in Christ, but one Lord Jesus acting in and through full divinity and full humanity. In putting the matter thusly, Athanasius is setting up what will become quite a nuanced consideration of the relationship between deity and humanity in the single person of the Christ. We will look into that momentarily.

For now, Athanasius gave expression to the rule of faith established in Nicaea. In 325, the church convened its first ecumenical council in order to decide the merits of Arianism. It rejected that school of thought, agreeing with Athanasius that prophetic and apostolic testimony to Christ present fully divine agency together with fully human agency, and declaring Arianism anathema. In a sense, then, Athanasius attained the upper hand over Arius. But we must be cautious about this. After the council condemned Arius, a series of political maneuvers took place, which compromised Athanasius’ position. In 335, he was exiled to what was then Gaul (modern Trier, Germany). Though he was allowed to return in 337, his battle with Arianism continued until his death. It was not until 8 years after he died that the Nicene decision was reinforced and expanded in the church’s second ecumenical council, Nicaea-Constantinople (381), and Athanasius was vindicated.

With the Athanasian/Nicene position that Christ is fully God and fully man, a single person possessing divine and human natures, the question surfaced as to the exact potency of these natures. Are they equally present and operative, or is one more directive than the other? Is Christ more determined and influenced by human qualities, or by divine?

Church fathers were divided about whether to place emphasis on either Christ’s divinity or humanity and, if so, where. Two schools of thought emerged, each accenting the operative significance of one nature over the other. Although boasting advocates from diverse locales, both schools took names from leading cities of christological discourse located in the eastern part of the Roman Empire. Not surprisingly given the controversy between Arius and Athanasius, the first school is the Alexandrian. The name of the second school is taken from the Syrian city Antioch where, according to the book of Acts (11:26), followers of Jesus were first called “Christians” and where study of the Gospels had been in full force since the time of Paul and Barnabas.

Alexandrian Christology initially gained ascendancy. A colleague of Athanasius provides our entry point into this set of material. His name was Apollinarius (c. 310–390). Keen to advance Athanasius’ cause against Arianism, Apollinarius famously taught that Jesus did not possess a human mind, but that he reasoned according to the wisdom of the divine Word or Logos. Reflecting classical anthropology, Apollinarius apparently believed that the mind is what makes the creature what it is. What makes man a man is his organ of the intellect. If Jesus thus possessed a human mind, He could not be divine.

Now Apollinarius does not represent Alexandrian Christology in its most sophisticated state. In fact, his teaching was eventually condemned at the council of Constantinople in 381, because his account of Christ did not adequately handle those passages in the Gospels where the human quality of Jesus’ cognition is clearly at work, for instance, in His ignorance of the day of judgment. But Apollinarius demonstrates the defining characteristic of the Alexandrian school. Alexandrian Christology accented the divinity of Christ. Alexandrian thought tended to emphasize the fact that Christ was the very Word of God. At times, the humanity of Christ is lost on this school, or at least rendered secondary to Jesus’ divinity. A view like that of Apollinarius might correct Arian subordinationism of the Son to the Father, but it does so at the expense of subordinating Jesus’ human nature to the Word.

Antiochene Christology, by contrast, accented the human nature of Christ. It emphasized that in Jesus of Nazareth the Logos of God assumed not just a fleshly body, but also full-fledged human nature. To a great extent, the Antiochene school provided a therapeutic corrective to the excesses of Alexandrianism. But this trajectory too becomes troublesome when focus on the human nature of Christ entails neglect of or short shrift given to the divine nature. This can occur by splitting off Jesus’ human nature from His divinity. Such is the legacy of Nestorius.

Nestorius (d. c. 451) was Bishop of Constantinople. He famously rejected the doctrine of “theotokos,” the teaching that Mary was literally the “bearer of God.” During the fourth-century christological debates, this term had become a handy, quick means of acknowledging that Jesus of Nazareth was fully God. It communicated the truth that Mary did not give birth to just a mortal man whom the Holy Spirit endowed with supernatural gifts. No, she gave birth to the Deity Himself. The extent of difficulty Nestorius had with this term has been exaggerated, but in any case we know that he was uncomfortable with its employ and preferred instead the designation Christotokos, “bearer of Christ.”

We can understand his hesitancy in part because of the logical problem that giving birth to God seems to entail: Can God really be born?

There is a certain warrant to Nestorius’ concern, but nonetheless he has become the poster child for christological heresy. Nestorianism falls short in part because Jesus Christ is indeed fully God, as the first two councils made clear, and so in some sense Mary is logically mother of God. The real problem, however, surfaces when Nestorius’ misgivings are carried through. The logical consequence of refusing to acknowledge that Mary bore the very God is that it becomes difficult to locate divinity in Jesus. Nestorians did not deny Christ’s divinity, but they had to speak of His divine nature in isolation from His conception. Whereas Alexandrian Christology could locate Jesus’ divinity in the “immaculate conception,” Nestorians, by refusing straightforwardly to allow that Mary gave birth to the Deity, had to treat Christ’s divine nature in abstraction from His human origin. When, exactly, does Jesus become divine if not at conception?

It is especially such division of the natures that Cyril (d. 444) vociferously rejected Bishop of Alexandria from 412 until his death. Cyril’s Christology proved highly significant for Orthodox Christianity.

Cyril became involved in a heated letter exchange with Nestorius. In this exchange, he pronounced a series of anathemas on Nestorianism, most of which revolved around any sort of formulation that breaks Christ into two distinct essences. He condemned any compromise of the confession that Christ is fully divine from conception even as He takes up human being. He insisted that Jesus’ natures are not isolated even as they retain their individual integrity, hence that in the incarnation of the Word we are dealing with a single person, who is in fact fully God and fully man.

In 431, the debate between Nestorianism and Cyrilianism had become heated enough that the emperor convened the church’s third ecumenical council, the Council of Ephesus. Partly because the Antiochene contingent arrived late, and partly because when the bishops did show up they were radically outnumbered, Nestorianism was condemned and its namesake forced to recant or go into exile. He chose the latter.

But this was not, by any stretch, the end of the matter. Nestorius continued to write in defense of his ideas in exile, and to command a following. Thus another step had to be taken. Even though the crucible of Christological conflict was centered in the East, it was a work from the West that paved a way forward.

In 449, Leo I, Bishop of Rome (d. 461), often called “Leo the Great,” wrote a letter to the Bishop of Constantinople. Generally referred to as Leo’s Tome, this letter set forth the primary decisions of the Western church on the essence of Christ’s person.

There is one element of Leo’s Tome to which we must give special attention. Leo uses the phrase “totus in suis, totus in nostris” with regards to Christ’s natures. Word-for-word he is confessing that Christ is “complete in what is His” and “complete in what is ours.” By what is ours, Leo does not include sin. Very importantly, he says the humanity that the Logos assumed is that which “the Creator formed in us at the beginning.” It is the nature given to Adam by God, before he fell, not the humanity that results as a consequence of Adam’s fall. That Christ becomes sin for us is an act of will on His part, not necessity. Leo refers specifically to Philippians 2 to make his point: “The ‘emptying of himself,’ by which the invisible God chose to become visible,” he writes, “and the Creator and Lord of all willed to be a mortal, was an inclination of compassion, not a failure of power.” In taking on the form of a servant and becoming nothing, the Son of God did not divest Himself of His divine attributes. Rather, He took on human attributes as part of His eternal character of love and grace.

So God becomes human but as God. His divine nature is not reduced in the incarnation. And conversely, God did not take up humanity in order to divinize it, to make it no longer really human. Leo writes that in Christ “each nature preserves its own characteristics without diminution.” He insists that Jesus is utterly God and man, or true God in the form of true man. Both natures are complete and working; one does not dominate the other.

This is significant because it teaches us to conceive of Jesus as a single agent. It is not that sometimes His divinity is in play and sometimes His humanity, but rather, any work of the Christ is a single action involving both His deity as well as His humanity. When Jesus heals, it is the one Christ healing and not just His divine nature. When Jesus cries, it is the one Christ crying and not just His human nature.

At the same time that Leo was crafting his understanding of Christ’s person, certain Alexandrians were pushing their success over Nestorianism at Ephesus. In particular, a monk from Constantinople named Eutyches took rejection of Nestorianism to a logical but unacceptable end. He concluded that before the incarnation there were indeed two natures awaiting union, but once that union took place it involved the coalescence of humanity into Christ’s divinity. Eutyches seems to have felt that divine nature so outstrips human nature that the two could not possibly coexist in full, mutual equality. Thus, he contended that Christ effectively possessed just one nature. This is called Monophysitism.

Because of persistent Nestorianism on one side and Alexandrian Monophysitism on the other, a fourth ecumenical council was convened in the city of Chalcedon in 451. This council, which involved the participation of around 600 bishops, was the largest of any to this time, and it gave the defining rule of faith for orthodox Christology. Its decisions endure down to today. The language of the council reflects the balanced views of Athanasius, Cyril, and Leo.

The one-sided claims of Arius, Apollinarius, Nestorius, and Eutyches are condemned. It confesses that Jesus was “of one substance with the Father in relation to His divinity,” and “of one substance with us in relation to His humanity.” Chalcedon concluded that in Christ two natures are mystically united in one person or “hypostasis,” the rough Greek equivalent to “person.”

This rule of faith is thus commonly known as the “Hypostatic Union.” The council used the phrase, “without confusion, without change, without division, and without separation” to express both the coexistence and unity of the divine and human natures.

Immediately after Chalcedon, Monophysitism found a home in pockets of Christian faith, notably in Ethiopia among Coptic Christians. And Arianism would resurface in diverse forms in successive generations of the church. These are important issues to be aware of, but we cannot pursue them. We must leave them to your further study and move on to consider the work and person of God being God a third time, the doctrine of the Holy Spirit.

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Lesson Materials

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