The Two Natures of Christ

There is a question in the Gospels that nobody in them can leave alone. The disciples ask it in a boat with the water going down: “What manner of man is this, that even the wind and the sea obey him?” The scribes ask it, scandalised, when he tells a paralysed man that his sins are forgiven: “Who can forgive sins but God only?” The high priest asks it under oath, and Pilate asks it wearily, and a centurion answers it at the foot of a cross. Everything else in Christianity waits on the answer, and for four hundred years the Church worked at saying it in words that could not be bent.

A question you cannot answer by halves

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It is tempting to think the great councils were arguments about words, fought by bishops with time on their hands. They were arguments about words in the way a surgeon’s hand is an argument about millimetres. Every one of the wrong answers on offer was reasonable, popular, and supported by bishops, emperors and holy men; and every one of them, followed out, quietly emptied the Gospel of the thing the Gospel is for.

Here is the shape of the problem in one sentence. If Jesus Christ is not truly God, then what happened on the Cross is a good man’s death, and a good man’s death cannot forgive your sins. If he is not truly a man, then what happened on the Cross happened to somebody who was not one of us, and none of us has been carried through death. And if he is somehow two people standing very close together — a man with God alongside him — then God has not actually come down to where we are; he has sent a representative.

So the Church had to hold three things at once, and could not let go of any of them. Fully God. Fully man. One single somebody. The history of the first seven councils is the history of holding all three while people pulled at each in turn.

And the Word was made flesh, and dwelt among us, (and we beheld his glory, the glory as of the only begotten of the Father,) full of grace and truth.

John 1:14

Two words that had to be prised apart

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The whole settlement turns on a distinction that ordinary speech does not make, and the Fathers had to make it before they could say anything true. It is the difference between what something is and who somebody is.

Nature (Greek physis, or ousia, essence) answers “what?”. It is the kind of thing you are, with everything that belongs to being that kind of thing — for us: a body, a soul, a mind, a will, a set of limits, a death. Person (Greek hypostasis, or prosopon) answers “who?”. It is the one who has the nature, the one who acts, the one you can address by name, the one who can be loved.

You and your neighbour share one human nature and are two persons. The Father, the Son and the Holy Spirit share one divine nature and are three Persons. And in Christ — this is the hard and precise thing — there is one Person who has two natures. He is not half of each. He is the whole of both, and he is one somebody.

Beware the analogies here; every one of them limps, and the ancient heresies are mostly analogies that were trusted too far. A red-hot iron in the fire is the old favourite — the iron is still iron and the fire still fire, and yet you may say “the iron burns” and “the fire cuts” of a single glowing bar. It is a good image and it is not the thing itself, and St John of Damascus, who liked it, said so.

Nicaea, 325: is he God at all?

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The first question had to be answered before the second could even be asked. Arius, a learned and ascetic priest of Alexandria, taught that the Son is the first and highest of all creatures — made before time, glorious beyond imagining, the instrument through whom everything else was made, but made. “There was when he was not.” It is a tidy doctrine. It keeps God safely transcendent and gives Jesus every honour short of the one that matters.

The council that met at Nicaea in 325 answered with a word that is not in the Bible, and knew it: homoousios — “of one essence” with the Father. They chose an unscriptural word because every scriptural word they tried had been signed by the Arians with a private meaning. Sometimes the only way to keep the Scripture’s sense is to say in a new word what it will not let you say in an old one.

St Athanasius, who spent seventeen years of his episcopate in exile for that word, put the reason for it in a single line that has never been improved on.

“He became man that we might become god.”St Athanasius the Great, On the Incarnation

That is not a metaphor and it is not a slogan. It is the exchange the whole faith rests on, and it only works if the one who came down is God and the place he came down to is our own human nature, without reduction at either end.

Constantinople, 381: is he all of a man?

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The next pull came from the opposite side, and from a friend. Apollinaris of Laodicea was a defender of Nicaea and a friend of Athanasius, and he reasoned like this: if Christ had a human mind, he would have a human mind’s wavering and ignorance and capacity for sin; so let the divine Word take the place of the human mind, and take flesh and an animal soul only.

It is a generous mistake — it is trying to protect Christ. St Gregory the Theologian answered it with the sentence that became the measuring rod of all later Christology, and it is worth learning by heart, because it settles more arguments than any other seven words in the Fathers.

“That which is not assumed is not healed.”St Gregory the Theologian, Letter 101 to Cledonius

Whatever part of us Christ did not take on, he did not save. If he had no human mind, the human mind is still where it was. If he had no human will, the human will is still where it was. Our minds are precisely the part of us most in need of healing, so a Christ without one would have healed the least of us and left the worst. The Second Ecumenical Council rejected Apollinaris in 381.

Ephesus, 431: is he one somebody?

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By now the Church had two facts it could not surrender: whole God, whole man. The next two centuries were spent working out how to put them into a single sentence without dropping either — and the two great schools of the East pulled in opposite directions.

Antioch was careful to keep the humanity real and unabsorbed. Alexandria was careful to keep the unity real and unbroken. Both instincts are right. Taken to an extreme, each becomes a heresy, and both extremes duly arrived.

Nestorius, Archbishop of Constantinople and a man of the Antiochene school, objected to calling the Virgin Mary Theotokos, “the one who gave birth to God”. Surely, he said, she gave birth to the man Jesus, and the Word was joined to him; call her Christ-bearer and be precise. The objection sounds modest. Follow it out and you have two sons: a divine Son eternally begotten, and a human son born in Bethlehem, associated with each other in a union of honour, grace and will — two somebodies, harmonised.

St Cyril of Alexandria saw immediately what that costs. If it is not God who was born, then it is not God who died, and if it is not God who died then the Cross is a tragedy rather than a redemption. The title Theotokos, he insisted, is not chiefly an honour paid to the Mother; it is a fence around the Son. The Council of Ephesus in 431 upheld it, and the Church has sung it ever since.

This is the place to say something that the history books often blur: the councils did not invent these titles. They defended words the Church was already praying. Theotokos was in the hymns of Egypt long before it was in the acts of a council — the prayer “Beneath thy compassion”, which uses it, is on a papyrus older than the dispute. Doctrine here is not an addition to prayer; it is prayer defended in court.

Chalcedon, 451: the sentence

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The opposite extreme came from a monk of Constantinople named Eutyches, an old and respected man and a fierce opponent of Nestorius. Pressed to say how the two natures stand after the union, he said what many simple believers half-thought: before the union, two; after the union, one. The humanity, he said, is in the divinity as a drop of honey in the sea.

If that is so, then the man in the Gospels is a kind of appearance, and everything human in him — the hunger in the wilderness, the tears at the tomb, the sweat in the garden, the cry from the Cross — is a performance rather than a real human life. And our humanity is not, after all, in heaven; it was dissolved on the way.

A council at Ephesus in 449 approved Eutyches by force and shouting — the Fathers afterwards called it the Robber Council. Two years later, at Chalcedon across the water from Constantinople, the largest council of the ancient Church met to undo it. The Tome of St Leo of Rome was read aloud, and it said with Latin clarity what the Greeks had been circling: each nature does what is proper to it, in communion with the other — the Word working wonders, the flesh enduring injuries — and both belong to one and the same Person.

The definition the council produced is the most carefully built sentence in Christian history, and it is almost entirely negative. It does not explain the union. It fences it. It says four things that must not be said, and leaves the mystery standing in the middle of them.

The four words, one at a time

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Without confusion — the two natures are not stirred together into a third thing that is neither. Christ is not a demigod, not a blend, not a divine-human alloy. God remains God and man remains man in him.

Without change — neither nature is turned into the other. The divinity is not reduced to fit inside a body; the humanity is not upgraded out of being human. When we say the Word “became” flesh we do not mean he stopped being what he was: he took what he was not, without losing what he was.

Without division — you may not parcel out the deeds. It is forbidden to say “the man wept and the God raised him”, as though two parties took turns. The one Person wept, and the one Person raised him; and because he is one, the humble things and the glorious things belong to the same somebody.

Without separation — the union never comes apart, not for an instant, not in the tomb, not for eternity. The human nature Christ took at the Annunciation he has still. There is a man in the Holy Trinity, and he has our address.

Read the four together and you see what they are doing: they mark out the four ditches on either side of a narrow road. Confusion and change are the ditch on the Alexandrian side; division and separation are the ditch on the Antiochene. The road between them is not a compromise. It is the only place from which both true things can be said at once.

The exchange of names

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One consequence of the unity is so strange that it is worth setting out on its own, because the Church’s hymns are full of it and a visitor can be forgiven for thinking they have misheard. The Fathers call it the communication of idioms — the exchange of properties. Because there is only one somebody in Christ, whatever is true of either nature may be said of him; and so the human things may be said of God, and the divine things may be said of the man.

That is why an Orthodox Christian may say, without any exaggeration and without any poetry, that God was born in a cave, that God was carried in the arms of a girl, that God was hungry, and — the hardest of them — that God died on a cross. Not the divine nature: the divine nature cannot be born and cannot die. But there is no such thing as a nature walking about on its own. Natures do not do things; somebody does things, in a nature. And the somebody here is the Son of God.

Listen for it on Great Friday, when the Church sings of “him who hangs upon the tree” and calls him the one “who hung the earth upon the waters”. Listen for it in the Nativity troparion, and in the burial service, and in half the Theotokia. These are not devotional flourishes; they are Chalcedon in the mouth of a choir, and a Church that had lost the doctrine would very soon have to stop singing them.

“Today he who hung the earth upon the waters is hung upon the tree.”The fifteenth antiphon, Matins of Great Friday

The rule has a limit, and the limit is important: the exchange runs through the Person, never directly between the natures. You may say “God died”, because the one who died is God. You may not say “the divinity died”, because that is a statement about a nature, and it is false. The whole of the Church’s daring speech about the Incarnation lives inside that distinction; take the distinction away and the same words become nonsense.

Three questions people actually ask

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Did he know everything? As God, yes; as man, he learned, and St Luke says so plainly: he “increased in wisdom and stature”. A real human mind grows, and his was real. When he says that of the day and the hour no one knows, not even the Son, he is not pretending. Knowledge belongs to a nature, and he has two — which is not a contradiction but the whole doctrine, applied.

Could he have sinned? He was genuinely tempted — Scripture insists on it — and he did not sin. The Fathers answer that he took our nature as it is since the Fall in everything blameless (hunger, weariness, pain, shrinking from death) but not in what is culpable; and that because the one who wills in that nature is the Son of God, the human will he took is unfailingly free — free in the way ours was made to be and no longer is. The temptation was real; the outcome was never in doubt, not because the humanity was a puppet, but because it was, at last, a human freedom that was not in bondage.

Why does it take so many words? Because each of them was cut to fit a wound. Nobody sat down to compose a definition of Christ for the pleasure of it; every clause in the sentence exists because somebody, often in good faith, had said the opposite and a great many people had believed them. The definition is short. It is the four hundred years behind it that are long.

Two more councils, and one man’s hand

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Chalcedon did not end the argument — it cost the Church the ancient communities of Egypt, Syria and Armenia, which are with us in much and not in this, and the conversation with them has gone on for fifteen hundred years. Two later councils had to finish the work.

The Fifth Council (Constantinople, 553) answered those who feared Chalcedon had conceded too much to Nestorius. It affirmed, in the sharpest terms the Church has ever used, that the one who was born of the Virgin and the one who was crucified is a Person of the Holy Trinity: “One of the Holy Trinity suffered in the flesh.” Not “the human part suffered while the divine part looked on”. The subject of the suffering is the Son of God — suffering, of course, in the nature that can suffer, since God as God cannot; but it is he who suffers, and that is the whole point.

The Sixth Council (Constantinople, 681) answered the last refinement. Monothelitism — “one will” — was a government compromise, offered in good faith to bring the Egyptian and Syrian churches back: let us say two natures, to satisfy Chalcedon, but only one will, to satisfy everyone else. It was accepted by emperors and by several patriarchs, and for a time by Rome.

It was refused by a monk. St Maximus the Confessor saw that willing belongs to a nature, not to a person — that to have a human nature is precisely to have a human way of willing — so a Christ with only a divine will has a crippled humanity, and the hardest moment in the Gospels becomes theatre. In Gethsemane “not my will, but thine, be done” is a real human will, shrinking from real death, and freely handing itself over. If there is no human will there, there is nothing being handed over, and our own willing — the very seat of our sin — is left untouched and unhealed.

For refusing, Maximus was tried, and when he would not yield his right hand was cut off and his tongue torn out, so that he could neither write nor speak; and he was exiled to the Caucasus, where he died. Nineteen years later the Church in council said what he had said: two natures, two natural wills, two natural energies — the human will never opposed to the divine, always freely following it. The doctrine of the two natures has a martyr, and that is worth remembering the next time it sounds like an argument about words.

Why it is not abstract

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Four consequences follow, and each of them touches an ordinary Sunday.

Your prayers reach somebody who knows. “We have not an high priest which cannot be touched with the feeling of our infirmities; but was in all points tempted like as we are, yet without sin.” Not a sympathetic observer — a participant. Fear, exhaustion, grief, the dread of dying: he has been inside them with a human mind and a human will, and not from the outside.

Forasmuch then as the children are partakers of flesh and blood, he also himself likewise took part of the same; that through death he might destroy him that had the power of death… Wherefore in all things it behoved him to be made like unto his brethren.

Hebrews 2:14, 17

The Eucharist is what the Church says it is. If the humanity were absorbed, there would be no human flesh to give; if the divinity were absent, there would be nothing life-giving in the giving. St Cyril called the Body of Christ “life-giving flesh” for exactly this reason — flesh, really; life-giving, because it is the flesh of God. What you come forward for on Sunday morning stands or falls with Chalcedon.

Icons are possible. The last of the seven councils, at Nicaea in 787, defended images on a purely Christological ground: God in his own nature has no likeness and cannot be drawn, and the one who took flesh of the Virgin has a face, a height, a colour of eyes. To say Christ cannot be depicted is to say something about his humanity — that it is not quite real, or not quite his. The wooden boards in the church are an argument from Chalcedon that you can see across the room.

And your own flesh has a future. The Transfiguration shows what the humanity of Christ is: not divinity wearing a disguise, but a real human nature so entirely God’s own that the glory comes through it without burning it away. That is what is promised to the rest of us — not that we shall become God by nature, which is impossible, but that everything a creature can receive of God’s own life will be given to a body and a soul like yours.

What we sing

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You do not have to take any of this on trust from a history page. It is sung at Saint Nina, and in every Orthodox church in the world, on an ordinary Sunday morning near the beginning of the Liturgy. The hymn is traditionally ascribed to the Emperor Justinian, who added it about the year 535, in the middle of exactly these disputes; and it is the whole of this article in one breath.

Count what is in it. Only-begotten Son and Word of God — Nicaea. Immortal — true God. Incarnate of the holy Theotokos — Ephesus. Without change didst become man — Chalcedon, one of its four words exactly. Wast crucified… one of the Holy Trinity — the Fifth Council. Four hundred years of argument, three hundred bishops, exiles, a severed hand, and it comes to rest in a hymn a child can learn, sung before the Gospel is read.

That is what the doctrine of the two natures is for. Not to explain the mystery — no one at Chalcedon imagined they had explained anything — but to keep the door open on both sides, so that when you say “Lord Jesus Christ, Son of God, have mercy on me”, the one you are speaking to is God, who can help, and man, who understands, and one single somebody, who is listening.