The two natures of Christ

Truly God and truly man

In the Gospels Jesus does what only God can do. When he forgave a paralysed man, the scribes asked, "Who can forgive sins but God alone?" (Mark 2:7), and they were right about that; Jesus answered by healing the man. Thomas, meeting the risen Lord, said, "My Lord and my God!" (John 20:28). Paul puts it in one line:

For in Christ all the fullness of the Deity dwells in bodily form.

Colossians 2:9

The same Jesus lived a fully human life. He sat down by a well, "weary from His journey" (John 4:6); at Lazarus' tomb "Jesus wept" (John 11:35). He was tempted in every way as we are, "yet was without sin" (Hebrews 4:15).

The church says this with the word ‘nature’, in Greek phusis (φύσις): what a being is. Christ's divine nature is all that God is, shared with the Father and the Spirit; his human nature is all that a human being is, a real body and a soul that thinks and wills. Yet these are not two people. They belong to one ‘who’, the Son of God. In Gethsemane he prayed, "Yet not as I will, but as You will" (Matthew 26:39). Augustine saw in that prayer that "Christ thus as man shews a certain private human will" Augustine, a human will that freely yielded to the will of God.

The fence of Chalcedon

The early church wrestled with explanations that made the mystery easier by cutting away one side. Nicaea (325) answered Arius by confessing the Son truly God; Constantinople (381) answered Apollinarius, who denied Christ a human mind, by confessing him fully man. Ephesus (431) guarded the one Christ against teaching that seemed to divide him in two (see Nestorianism). When Eutyches said that after the union there was only one nature, the Council of Chalcedon (451) confessed:

one and the same Christ, Son, Lord, Only-begotten, to be acknowledged in two natures, inconfusedly, unchangeably, indivisibly, inseparably

The Definition of Chalcedon

The first two words fence off mixing the natures into some third thing; the last two fence off dividing Christ into two subjects. The council received the letter of Leo of Rome, which taught that each nature keeps its own character and acts in communion with the other in one person Leo the Great, Tome. How the two are one is the subject of the hypostatic union.

In the seventh century some taught that Christ had only one will. The Third Council of Constantinople (680–681) confessed two wills in him, divine and human, the human will not resisting but following the divine. The church judged that if Christ had not taken a human will, our wills would not be healed.

Churches that did not receive Chalcedon

The Oriental Orthodox churches, among them the Coptic, Armenian, Ethiopian and Syriac churches, did not accept Chalcedon. They feared that ‘in two natures’ opened the way to dividing Christ, and they confess with Cyril of Alexandria ‘one incarnate nature of God the Word’. By one nature they do not mean a blend of divine and human, but the one Word made flesh without mixture or change; they too reject Eutyches and do not accept the name monophysite. The Eastern Orthodox, Catholic and Protestant churches have kept ‘in two natures’. Since the later twentieth century, dialogues between the two families have found that, despite different words, they largely share the same faith in Christ, though full communion has not been restored.

Protestant churches all confess Chalcedon, though Lutherans and the Reformed explain differently how the properties of each nature are shared in the one person. This matters for daily faith: the "one mediator between God and men" is "the man Christ Jesus" (1 Timothy 2:5). Because he is God he can save us; because he is man he stands beside us. See also the lesson Truly God and truly man and Who is Jesus?