Who is God? What is he like, and how do we come to know him? What is salvation?

We may be tempted to consign these questions to the first weeks of evangelistic courses or the earliest years of discipleship, yet they were central to the ministry of Cyril of Alexandria (c. AD 376–444). As a bishop and theologian with far-reaching influence, he saw the gravity of these questions, as well as the pastoral fallout if Christians thoughtlessly rattled off pat answers.

Cyril’s heart was that believers would consciously and joyfully place Jesus Christ front and center in their understanding of God and their salvation. His tenacious Christ-centeredness shaped some of the most significant all-church councils and creeds that we have inherited today.

Seeds of Scandal

In the fifth century, perhaps the most famous church in the world was the Great Church of Constantinople. Enthroned there in the heart of the “New Rome,” its archbishop carried a leading political and theological voice. In 428, the job was given to a well-loved Syrian preacher named Nestorius.

Nestorius wanted to stop all references to Mary as theotokos, Greek for “Mother of God.” The title had long been popular and had tried to express something of the wonder of the incarnation: that a human mother should give birth to God the Son in human flesh. In Nestorius’s mind, however, the title was imprecise and dangerous. His concern was not that it encouraged undue veneration of Mary (that would develop later in church history), but that it implied something about God that he could not accept.

That God should be born, naked and crying, depending on a mother to feed and wash him, was unthinkable. God, eternally unchanging and untouchable, simply could not be straightforwardly identified with the wriggling baby in the manger. No, Mary must be called “Mother of Christ,” not “Mother of God.” There had to be a clear distinction between the two. Nestorius devoted a sermon series to the subject, and his troubled colleagues began to ask, If Mary is not the “Mother of God,” then just who is her son?

Nearly seven hundred miles to the south in Egypt, Cyril, the archbishop of Alexandria, was alerted to the emerging scandal. Having spent years writing biblical commentaries and theological works on the Trinity, he knew he had to step in and challenge Nestorius. Like the apostle Paul centuries before, Cyril saw that when the identity of Jesus Christ is distorted, so is our understanding of God and what it means to know him — with devastating consequences. “Another Jesus” goes hand in hand with “another gospel” (2 Corinthians 11:4).

Another Jesus

Nestorius believed in Jesus as the eternal Son and Word of God. He believed, along with the Council of Nicaea of AD 325, in the humanity and divinity of Christ. Yet the distortion of Jesus he presented threatened to undo the orthodox faith he claimed to hold.

“‘Another Jesus’ goes hand in hand with ‘another gospel.’”

Nestorius’s deepest problem was that he had his definition of God prepared long before he came to look at the person of Jesus Christ. The carpenter from Nazareth, in the manger and on the cross, could not fit with his understanding of God. Following his mentor, Theodore of Mopsuestia (c. 350–428), Nestorius taught that Mary’s son was a separate man from God the Son: a man assumed (taken up) and brought into fellowship with God. Jesus and the Word enjoyed a relationship of unique cooperation, with the Word graciously sharing the honor of his sonship with Jesus. Because of his obedience, Jesus came to earn his resurrection into a new life free from death and decay (Nestorius, Bazaar of Heracleides, 1.3).

For Nestorius, although the people of first-century Israel saw an individual human being with divine power, they were actually looking at a kind of partnership of two sons, presented in one man. A glass wall ran down the middle of Jesus Christ, shielding the eternal Word from the human experiences and troubles of the man until he was perfected. While Nestorius was happy to worship and adore the man Jesus, he did so only beside “the one who bears him” (Sermon 9.262).

Cyril could see that Nestorius’s Jesus was only a man like the rest of us, elevated to a special relationship with God. The one who suffered and died on the cross was not technically God the Son himself coming to us in the flesh. Instead, God wore gloves, as it were, to deal with sinful humanity. He promoted a man to divine dignity, setting before us a supercharged example of holiness to imitate. Nestorius’s Jesus is the perfect Savior for those who would win salvation for themselves.

The Real Jesus

In AD 431, at the Council of Ephesus, Cyril (along with most of the other bishops) opposed Nestorius’s teaching. They saw that it contradicted not only the biblical Jesus but also the biblical gospel. Leaning heavily on Cyril’s writings, the fathers of the church affirmed that while there are two natures in Christ, there is only one person.

In other words, God the Son was the person in action during the incarnation, whether he was walking on water by the Spirit or tired after a journey in his flesh. He maintained his unchanged, eternal divine nature, but had added to himself a truly human nature — along with all of its capacity to fall asleep in a boat, battle temptation, or suffer crucifixion.

“The Son of Mary was none other than God the Son himself, made known and living in human nature as well as divine.”

God the Son personally took all that we are to himself, choosing this way of being “for us and for our salvation,” as the old Nicene Creed had it. In answer to the question of the pastors of Constantinople, the leaders gathered at Ephesus were clear: the son of Mary was none other than God the Son himself, made known and living as man as well as divine.

Cyril’s Influence

In time, this picture of Christ came to be known as the “hypostatic union”: a true union of divine and human in the one person (Greek hypostasis) of God the Word. It was not an agreement between two parties with separate agendas, nor a cooperation of equals.

In fact, there was a critical asymmetry to this union, for the humanity of Jesus comprised no separate person, as Nestorius had taught, but was “personated” by the Son. Humanity had been added to a preexisting divine person. There was no Jesus to know other than the second Person of the Trinity, now made flesh. This meant that all of Jesus’s actions and words were truly the actions and words of God the Son.

Just as it was right to call Mary theotokos, so it was right to say that God the Son played in the streets of Nazareth as a child, that God the Son had compassion on lost and helpless sinners (Mark 6:34), that God the Son shed his blood on the cross for our redemption (Acts 20:28). For it was no other person, no other human, but only the eternal Word in his humanity. After all, he was Immanuel, God with us.

These biblical convictions were honed and clarified by another all-church council held in Chalcedon in AD 451. Responding to another stream of false teaching, the church again turned to Cyril’s Christology (though he had now been dead some seven years). The gathered bishops affirmed that the one person of Jesus Christ was to be acknowledged in two “unconfused, unchangeable, indivisible, inseparable” natures. They confessed that the divine and the human in no way undermined or undid one another, yet that he was nevertheless just one person: “one and the same Son” who was with the Father before all things and who was born of Mary for us and our salvation. Chalcedon rang deeply with the echo of Cyril’s theology.

God Was Pleased

Nestorius’s precooked doctrine of God meant that he struggled to get divinity and humanity in the same person. There was an unbridgeable gulf between the divine and human, and his theology left believers the task of crossing it on their own, following at a distance in the footsteps of a superman from Nazareth.

Cyril, however, began with Jesus and allowed the Son of God to reveal the nature of God (John 1:18). And the God revealed in Jesus, he saw, was pleased to draw near to sinful humanity in person (Colossians 1:19¬–20). He came in uncompromised deity, but with mind-bending condescension, to cross the divide himself. The Son stepped in, clothed in our humanity, laying down his life, and taking hold of us when we could not save ourselves. In Jesus, God truly demonstrates his love for undeserving sinners, up close and personal.