• Keith Mathison

Jesus Christ: Truly God, Truly Man



When we open any of the four Gospels, we read of the birth, life, death, and resurrection of Jesus of Nazareth. If we look closely at what we read, one thing that will catch our attention is that Jesus often says and does things that that only a human being can say or do, and He also often says and does things that only God can say or do. For example, He ate (Mark 2:15–16). He drank (John 19:30). He grew weary (John 4:6) and slept (Mark 4:38). In other words, He was truly human.

Yet, what else does Jesus say and do? He says things that imply He eternally existed prior to His incarnation (e.g., John 3:13; 6:62; 8:42). He forgives sins (Matt. 9:6; Mark 2:10; Luke 5:24). He hears and answers prayer (John 14:13–14). He receives worship and praise (Matt. 21:16). In short, He says and does things indicating that He understands Himself to be truly God.

After the death, resurrection, and ascension of Christ, the Church found itself having to answer questions about Jesus – questions that came not only from inquirers and skeptics outside the church but also from catechumens and laity within the church. How can we say both kinds of things about Jesus? Is He a human being? Is He a divine being? Is He a third kind of being, some mixture of deity and humanity? Scripture was forcing the Church to ask and answer philosophical questions, specifically, metaphysical questions about being.

These kinds of questions and others resulted in a large number of wrong answers. These wrong answers are the early Christological heresies. All of them are wrong because they all either fail to take into account everything Scripture says about Jesus or else deliberately reject one part or another of the biblical testimony. Some, for example, attempted to solve the difficulty by rejecting the true humanity of Jesus. These were the docetists. The Ebionites solved the difficulty in the opposite way by denying the true deity of Christ.

Adoptionists argued that Jesus was not the eternal Son of God. Instead He was a human being who was adopted as the Son of God at His baptism. Modalists, such as Noetus and Sabellius, argued that the Father, Son, and Holy Spirit were different “modes” of the one God. Sometimes this one God wears the Father mask. Sometimes He wears the Son mask. Other times He wears the Holy Spirit mask. All of these views were decisively rejected by the Church as being out of accord with the teaching of Scripture.

The suggested solution offered by Arius ignited the fourth century Trinitarian controversy. In brief, Arius argued that the Son is a creature. He did not exist eternally, so there was a “time” when the Son was not. Various forms of Arianism developed during the fourth century. What they all have in common is a strong subordinationist strain. For example, the Second Creed of Sirmium, written by fourth-century Homoian Arians, states:

There is no uncertainty about the Father being greater: it cannot be doubted by anyone that the Father is greater in honor, in dignity, in glory, in majesty, in the very name of ‘Father.’

This teaching stood in direct contrast to the Nicene Creed which was produced at the Council of Nicaea in AD 325. Because the controversies did not immediately end after 325, another council, the Council of Constantinople was called in AD 381. The original Nicene Creed was expanded into the form most are familiar with today:

We believe in one God, the Father Almighty, Maker of heaven and earth, and of all things visible and invisible.

And in one Lord Jesus Christ, the only begotten of the Father before all worlds; God of God, Light of Light, very God of very God; begotten, not made, being of one substance with the Father, by whom all things were made. Who, for us men and for our salvation, came down from heaven, and was incarnate by the Holy Spirit of the virgin Mary, and was made man; and was crucified also for us under Pontius Pilate; He suffered and was buried; and the third day He rose again, according to the Scriptures; and ascended into heaven, and sits on the right hand of the Father and He shall come again, with glory, to judge the quick and the dead; whose kingdom shall have no end.

And we believe in the Holy Ghost, The Lord and Giver of life; who proceeds from the Father and the Son; who with the Father and the Son together is worshipped and glorified; who spoke by the prophets. And I believe in one holy catholic and apostolic Church. I acknowledge one baptism for the remission of sins; and I look for the resurrection of the dead, and the life of the world to come. Amen.

This creed was used to express what the Church believed the Scripture to be teaching about God the Father, Son, and Holy Spirit. [Note that the creed is not Scripture. Scripture is the Word of God, saying, “Thus saith the Lord.” The Creed is the word of the Church, responding, “We believe.”]

With the dust having barely settled from the fourth century controversy, a new controversy arose among those who professed the Nicene Creed. One school of thought developed a way of talking about Christ that can best be termed a “Two Sons” theology. Diodore of Tarsus and Theodore of Mopsuestia so divided the human and divine in Christ that they were effectively left with two sons: the Son of God and the Son of Mary. The problem was that they couldn’t clearly identify the one with the other.

The next phase of the controversy exploded when Nestorius, bishop of Constantinople and a proponent of “Two Sons” doctrine, entered into a heated debate with Cyril, the bishop of Alexandria. Cyril insisted that both Scripture and the Nicene Creed teach the same thing, namely that there is only one Jesus in Scripture and that the Son of Mary is the Son of God incarnate. The controversy eventually resulted in the Council of Ephesus (AD 431) and the condemnation of Nestorius and his teaching.

In the West, Leo, the bishop of Rome, found himself addressing the teaching of the presbyter Eutyches, an opponent of Nestorianism who had run to a different extreme. His view, as best we can tell, involved the idea that the divine nature and human nature were somehow mixed together in the one Person of Christ. Leo refuted the Eutychian teaching in a letter today known as the Tome of Leo.

The Council of Chalcedon, which convened in AD 451, addressed both Nestorianism and Eutychianism. The written document the council produced is several pages long. It states that anyone wanting a full explanation of biblical Christology should read the letters of Cyril of Alexandria to Nestorius and the Tome of Leo regarding Eutychianism. The Council summarizes the orthodox doctrine of the Person of Christ in the penultimate paragraph, the Definition of Chalcedon, which reads as follows:

So, following the saintly 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; consubstantial with the Father as regards his divinity, and the same consubstantial 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 the same for us and for our salvation from Mary, the virgin God-bearer as regards his humanity; 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.

We might summarize the Christological teaching of this paragraph under four main points:

  1. Jesus is “One and the same” Son: This phrase “one and the same” is repeated three times, emphasizing its importance. It is stated at the beginning, in the middle, and at the end of the Chalcedonian Definition of Faith. The point being made is that Jesus Christ is a single person, a single subject, namely the Son of God incarnate. There are not two Sons or two Christs.

  2. Jesus is perfect in His divinity and perfect in His humanity. In other words, the one Jesus is truly God and truly man. The Definition also reveals that the one Jesus can be spoken of in terms of either of His two natures. It says that the one Jesus is:

  3. Homoousios with the Father regarding His divine nature

  4. Homoousios with us regarding His human nature

  5. Eternally begotten/generated of the Father regarding His divine nature

  6. Temporally born of Mary regarding His human nature. Because Jesus is truly God incarnate, the Definition speaks of Mary as “theotokos.” In other words, it affirms the deity of Christ even in the womb of Mary.

  7. The two natures of Christ are united without confusion or change. With these words, the Definition rejects Eutychianism.

  8. This means the property of both natures is preserved.

  9. The divine nature has all of the attributes of deity. The human nature has all of the attributes of human beings.

  10. The two natures of Christ are without division, or separation. With these words, the Definition rejects Nestorianism.

  11. The two natures come together in a single person.

  12. The one Person is not divided into two persons.

  13. The one Person is the only-begotten Son of God.

The Nicene Creed and the Definition of Chalcedon are vitally important subordinate theological standards in the Church. Both have been received and confessed by the historic Reformed churches. Their doctrinal content was affirmed by the early Reformed theologians and embedded in our confessions of faith because they express the teaching of Scripture.


Because there are those today who claim to adhere to Nicene Trinitarianism and to Chalcedonian Christology while at the same time teaching elements of the doctrines of the ancient opponents of Nicene Trinitarianism and Chalcedonian Christology, it is more important than ever for Christians to study these biblical doctrines.

Image by Steve Buissinne from Pixabay

Drop Me a Line, Let Me Know What You Think of the Blog

© 2023 by Train of Thoughts. Proudly created with Wix.com