The Two Natures of Christ

The definition of Chalcedon piles up its affirmations deliberately: Christ is "perfect in Godhead and also perfect in manhood; truly God and truly man… in all things like unto us, without sin." Consubstantial — of one essence — with the Father in His divinity, He is equally consubstantial with us in His humanity. Whatever it means to be God, He is; whatever it means to be human — a real body, a real soul, a human mind, and even a human will — He has. The only human thing He does not share is sin, which is not part of true human nature but its disease.

The Gospels show both natures in almost every scene. He sleeps, exhausted, in the stern of a boat — then rises and commands the sea, "Peace, be still." He asks where Lazarus is laid and weeps — then calls the dead man out of the tomb. St. Gregory the Theologian turned this double vision into a litany of wonder: "He hungered — but He fed thousands… He was wearied, but He is the Rest of them that are weary and heavy laden… He dies, but He gives life, and by His death destroys death."

Without confusion and without change guard against blending. The two natures do not melt into a hybrid — a demigod who would be neither truly God nor truly man; the humanity is not swallowed up by the divinity, and the divine nature does not turn into flesh. This answers Eutyches and the one-nature teaching. Without division and without separation guard the other flank: the natures cannot be pried apart into two sons or two Christs, with the miracles assigned to one and the sufferings to the other, as nestorianism risked doing.

Notice that all four are negations. The Church did not claim to explain how the infinite God and a finite man are one Christ; it marked the boundaries beyond which the mystery is lost. Within that fence the union is as intimate as it can possibly be — one Person subsisting in both natures — while each nature keeps its own integrity, "the property of each nature being preserved," as the definition says. Orthodox theology is content to live inside this holy tension rather than resolve it.

Cut either nature and salvation unravels. If Christ is not fully God, His life and death are one more human story — admirable, but powerless; no creature can conquer death or join humanity to God. If He is not fully man — if His body only seemed real, or if the divine Word replaced His human mind, as apollinarianism taught — then whatever He did not take up remains untouched by His victory. St. Gregory's rule cuts both ways: "That which He has not assumed He has not healed; but that which is united to His Godhead is also saved."

This is also why the two natures are not a temporary arrangement for thirty-three years. Risen and ascended, Christ remains man forever; a human body and soul now live at the right hand of the Father. Every prayer addressed to Christ, every Liturgy, every hope of union with God rests on this: in one Person, God has become everything we are, so that everything we are can be brought home to God.