From time to time I make new entries into this continuing series called “Theological Primer.” The idea is to present big theological concepts in around 500 words. Today we look at the hypostatic union.
In simplest terms, the hypostatic union is a reference to Jesus Christ as both God and man, fully divine and fully human. Hypostasis is the Greek word for subsistence (think: individual existence). The hypostatic union, therefore, is the technical term for the unipersonality of Christ, whereby in the incarnation the Son of God was constituted a complex person with both a human and a divine nature.
For a concise and careful definition of the hypostatic union, the Chalcedonian Definition (AD 451) is still unsurpassed.
Therefore, following the holy fathers, we all with one accord teach men to acknowledge one and the same Son, our Lord Jesus Christ, at once complete in Godhead and complete in manhood, truly God and truly man, consisting also of a reasonable soul and body; of one substance with the Father as regards his Godhead, and at the same time of one substance with us as regards his manhood; like us in all respects, apart from sin; as regards his Godhead, begotten of the Father before the ages, but yet as regards his manhood begotten, for us men and for our salvation, of Mary the Virgin, the God-bearer; one and the same Christ, Son, Lord, Only-begotten, recognized in two natures, without confusion, without change, without division, without separation; the distinction of natures being in no way annulled by the union, but rather the characteristics of each nature being preserved and coming together to form one person and subsistence, not as parted or separated into two persons, but one and the same Son and Only-begotten God the Word, Lord Jesus Christ; even as the prophets from earliest times spoke of him, and our Lord Jesus Christ himself taught us, and the creed of the fathers has handed down to us.
At the heart of this definition are the four negative statements I’ve italicized above.
Without confusion: The Lord Jesus Christ is not what you get when you mix blue and yellow together and end up with green. He’s not a tertium quid (a third thing), the result of mixing a divine and human nature.
Without change: In assuming human flesh, the Logos did not cease to be what he had always been. The incarnation affected no substantial change in the divine Son.
Without division: The two natures of Christ do not represent a split in the divine Person. Jesus Christ is not half God and half man.
Without separation: The union of the human and divine in the person of Jesus Christ is a real, organic union, not simply a moral sympathy or relational partnership.
This may seem like needless theological wrangling, but Chalcedon’s careful definition is meant to preserve the biblical teaching that (1) the divine nature was united, in the person of the Son, with a human nature (John 1:14; Rom. 8:3; 1 Tim. 3:16; Heb. 2:11-14) and (2) the two natures are united in only one divine Person (Rom. 1:3-4; Gal. 4:4-5; Phil. 2:6-11). As Chalcedon puts it, the characteristics of each nature are preserved—in no way annulled by the union—even as they come together in one person (prospon) and one subsistence (hypostasis).