But if his human nature is not present wherever his Godhead is, are not then these two natures in Christ separated from one another?
Not at all, for since the Godhead is illimitable and omnipresent, it must necessarily follow that the same is beyond the limits of the human nature he assumed, and yet is nevertheless in this human nature, and remains personally united to it.
-Heidelberg Catechism, Q. 48
The hypostatic union is a great mystery of the Christian faith that our church fathers confessed over against a variety of Christological heresies. For example, in the fifth century the Definition of Chalcedon affirmed that the incarnate Son is both true God and true man, the one person of Christ subsisting in two natures. Yet these natures are not confused nor are they divided but the properties of each nature are conserved and concur in one person. To preserve the integrity of the Son’s divinity, the church fathers refused to limit the Son to the human nature he assumed. Even when Jesus walked the earth, he continued to uphold the universe by the word of his power (Heb. 1:2; Col. 1:17).
This belief became known as the “extra” and took on great importance in the heat of debates between Reformed and Lutheran theologians during the Reformation. Although Calvin’s name was attached to this doctrine and called the extra Calvinisticum, many others like Zwingli and Peter Martyr Vermigli taught the extra as well. However, the rise of Kenotic Christology in the last century threatens the extra, compromising the divine nature of Christ. At the heart of the matter is the question, how can Jesus be true man and yet remain true God?
In this episode, K.J. Drake joins Matthew Barrett to help us think through the extra Calvinisticum, explaining how the doctrine beautifully upholds Christ’s humanity but without compromising his divinity in the hypostatic union.
K.J. Drake is Assistant Professor of History at Redeemer University in Hamilton, Ontario. He is the author of The Flesh of the Word: The extra Calvinisticum from Zwingli to Early Orthodoxy.
Matthew Barrett is the author of Simply Trinity: The Unmanipulated Father, Son, and Holy Spirit (Baker). He is the founder and executive editor of Credo Magazine and host of the Credo podcast. He is associate professor of Christian theology at Midwestern Baptist Theological Seminary.