The Creed of Chalcedon
to be acknowledged in two natures,…without division
So the human and divine natures of Christ are not mingled together, nor are they changed by virtue of the union. What else did the Fathers at Chalcedon deem necessary for a proper understanding of the relation of the two natures in the person of the one and only Son of God? Well, we learn next that they thought it essential to believe that the two natures not be divided. This means that the human and divine natures of our Lord were forever united when the Holy Spirit overshadowed Mary in that wonderful mystery we call the virginal conception.
We are again taken back to controversies in the Early Church. If the Monophysites swallowed the human nature up into the divine, the Nestorians so divided the two natures as to make the union between the human and divine natures merely moral, that is, not a true union of the two natures at all but a man closely walking with God. The heresy originated with Nestorius, a fifth-century heretic who taught not a union of the two natures but a mere “junction” of the two in dignity and power. In short, Nestorianism led to there being two persons in one body, a schizophrenic christ of two natures and two minds. This the bishops condemned. In short, we may say that whereas the qualifiers “without confusion, without change” were to guard the integrity of each nature as human and divine, “without division [and tomorrow’s devotion] without separation” were to guard the unity of the person composed of the two natures.
And to insist upon the unity of the person of the only-begotten Son is just as important as to insist upon the integrity of both natures comprising the Son. We worship one and the same Christ, Son, Lord, and only-begotten of two natures, of course, but still one and the same Son. To divide the human from the divine nature of Christ is to exchange the God-man for a man-God; that is, a good man, a holy man, perhaps the holiest man ever, but in the end only a son of God and not the Son of God. This was the error of the Nestorians, and is the error of millions—both unbelievers and, sadly, professing believers—today.
The Gospel of John thunders: “The Word became flesh” (1:14). This is what the Creeds are referring to when they say, “He came down from heaven.” That coming down involved conception and the gestational process, superintended by the Holy Spirit, to be sure. In truth then, “What, therefore, God has joined together, let not man separate” (Mark 10:9).