Article by Dr. Nicholas Needham, minister of Inverness Reformed Baptist Church in Inverness, Scotland, and lecturer in church history at Highland Theological College in Dingwall, Scotland. He is author of 2,000 Years of Christ’s Power.

It’s hard enough to pronounce “Chalcedon.” Getting to grips with its theology can be even more daunting. But the effort will be very richly rewarded. For the past 1,500 years, right up to the present day, virtually all orthodox Christian theologians have defined their “orthodoxy” with reference to the Council of Chalcedon. That certainly includes the Reformed tradition. We may not think that the early ecumenical councils were infallible. But we have generally held that they were gloriously right in what they affirmed, and that Christians who take the church and its history seriously must reckon with these great councils as providential landmarks in the unfolding life story of God’s people.

What was Chalcedon all about? Basically it was trying to settle the aftermath of the Arian controversy in the fourth century. Biblical theologians had struggled successfully against Arianism to affirm the deity of Christ. But this led to further controversy. This time, the issue was the relationship between the divine and the human in Christ. Two tendencies quickly became prominent. One was associated with the church in Antioch. It wanted to protect the full reality of Christ’s deity and humanity. To do this, it tended to keep them as far apart as possible. The Antiochenes were afraid that any close blending of the two natures might mix them up. Christ’s human limitations might get applied to His deity — in which case He wasn’t fully God. Or His divine attributes might get applied to His humanity — in which case He wasn’t fully human. This was fine, as far as it went. The trouble was, Antiochenes sometimes separated Christ’s two natures so much, He seemed to end up as two persons: a human son of Mary indwelt by a divine Son of God. The most famous Antiochene thinker who took this line was Nestorius, a preacher who became patriarch (chief bishop) of Constantinople in 428. Nestorius was condemned by the third ecumenical Council of Ephesus in 431 (it also condemned Pelagianism as heresy).

The other tendency was associated with the church of Alexandria. Their main concern was to protect the divine person of the Son as the one single “subject” of the incarnation. In other words, there is in Christ only one “I,” only one personal agent, and this is the second person of the Trinity, God the Son. And again, this was fine as far as it went. The trouble was, Alexandrians sometimes became so zealous for Christ’s divine person, they could lose sight of His humanity. To the extremists of Alexandria, any sort of emphasis on Christ’s human nature seemed to threaten the sovereignty of His single divine person. Would Christ not break apart into two persons — the hated Nestorian heresy — if one insisted too much on the full reality of His manhood?

In the aftermath of Nestorius’ condemnation at Ephesus in 431, the Alexandrians made all the running. Their greatest thinker was Cyril of Alexandria. But when Cyril died in 444, a more extreme figure stepped into his place. This was Eutyches, a leading monk in Constantinople. Eutyches was so violent in his commitment to Christ’s single divine person, he could tolerate no rivalry (as it were) from His humanity. So in an infamous phrase, Eutyches taught that in the incarnation, Christ’s human nature had been swallowed up and lost in His divinity: “like a drop of wine in the sea.” This extreme Alexandrian view triumphed at another ecumenical council in Ephesus in 449. Its victory, however, was due less to theological argument and persuasion, and due more to gangs of unruly Alexandrian monks who terrorized the proceedings, supported by the troops of emperor Theodosius II, who favored Eutyches.

The council was condemned in the western, Latin-speaking half of the Roman Empire. Pope Leo the Great thundered against it as the “Robber Synod” (and the name stuck). After the death of emperor Theodosius, a new emperor, Marcian, called a new council at Chalcedon (in Asia Minor) in 451. This time, Eutyches and the extreme Alexandrians were defeated. The council skillfully wove together all that was good and true in the Antiochene and Alexandrian outlooks, producing a theological masterpiece on the person of Christ:

So, following the holy fathers, we all with one voice teach the confession of one and the same Son, our Lord Jesus Christ: the same perfect in divinity and perfect in humanity, the same truly God and truly man, of a rational soul and a body; of one essence with the Father as regards his divinity, and the same of one essence with us as regards his humanity; like us in all respects except for sin; begotten before the ages from the Father as regards his divinity, and in the last days, for us and for our salvation, the same born of Mary, the virgin God-bearer, as regards his humanity.

He is one and the same Christ, Son, Lord, Only-begotten, acknowledged in two natures which undergo no confusion, no change, no division, no separation. At no point was the difference between the natures taken away through the union, but rather the property of both natures is preserved and comes together into a single person and a single subsistent being. He is not parted or divided into two persons, but is one and the same only-begotten Son, God, Word, Lord Jesus Christ, just as the prophets taught from the beginning about Him, and as the Lord Jesus Christ Himself instructed us, and as the creed of the fathers handed it down to us.

Perhaps we can best appreciate what the Council of Chalcedon achieved by asking what the consequences would have been if either Nestorius or Eutyches had won the day. Let’s take Nestorianism first. If the incarnation is really a case of a human son of Mary being indwelt by a divine Son of God, then Christ is no different in principle from any holy human. Every sanctified man is indwelt by the Son. Was Christ merely the highest example of that? If so, no true incarnation has taken place at all. We cannot say “Jesus of Nazareth is the Son of God.” We can only say “Jesus of Nazareth had a relationship with the Son of God.” Think of what this does to our doctrine of the atonement. We would have to say we are saved by the sufferings of a merely human Jesus who happened to be indwelt by God (as all holy people are). Would that not inevitably lead to a belief that human suffering — perhaps our own — can atone for our sins? And think of what it would do to our worship. We would not be able to worship Jesus — only the divine Son by whom Jesus was indwelt. That would destroy Christian worship entirely.

But then, think what would have happened if Eutychianism had won out. If Christ’s humanity was lost and swallowed up in His deity “like a drop of wine in the sea,” then once again, no real incarnation has taken place. Rather than God becoming man, we have man being annihilated in God. One can see how this would easily have lent itself to all manner of humanity-denying mysticism. After all, if Christ is our pattern, shouldn’t we too seek for our own humanity to be lost and swallowed up in deity like a drop of wine in the sea?

The fathers at Chalcedon set themselves firmly against both of these unwholesome tendencies. They affirmed that Christ is indeed one single divine person, not some alliance of a divine and a human person, as in Nestorianism. The subject, the “I,” the personal agent whom we meet in Jesus Christ is singular, not plural; this person is “the Only-begotten Son, God, Word, Lord” — the second person of the Godhead. Mary is therefore rightly called the “God-bearer,” a truth passionately rejected by Nestorius. The person whom Mary bore was precisely God the Son! Mary is the mother of God incarnate (although not, of course, the mother of the divine nature). The fathers of Chalcedon equally affirmed that this one person exists in two distinct natures, complete deity and complete humanity, thus rejecting the Eutychian absorption of one into the other. We see in Christ everything that it is to be human, and everything that it is to be divine, at one and the same time, without either being compromised by the other. We could say that in Christ, for the first time and the last, all the fullness of human being, and all the fullness of divine being, have come together and exist together in exactly the same way — as the Son of the Father and the Bearer of the Holy Spirit. Or to put it more simply, Christ is fully and truly man, fully and truly God, at the same time, in a single person.

Veiled in flesh the Godhead see; 
Hail the incarnate deity! 
Pleased as Man with man to appear: 
Jesus, our Emmanuel here.

The fathers of Chalcedon did a fine job. In matters christological, we can perhaps only ever be dwarfs on their giant shoulders. We may be enabled to see even further, if we sit there. But if we climb off, I somehow doubt that we’ll see anything but Nestorian and Eutychian mud.