The incarnation is, of course, expressed and grounded in the Bible. We believe in the incarnation because it’s revealed in the Bible. And this revelation has been captured for us in various creeds from the early centuries of Christian history. Most important in looking at the incarnation is the creed known as the Chalcedonian Creed.
Chalcedon is essentially a marking out of the boundaries of what makes up orthodoxy and then everything else. If what you believe is coherent with Chalcedon you’re on a good chance of being orthodox, if it doesn’t play within the boundaries you’re probably starting a new religion.
But before we look at that creed it would be good to just clarify what we mean by the word “incarnation”. Because it’s not really a word we use very often. The only time we really come close is the dish Chilli Con Carne. And what that means is “Chilli with Meat”. The word incarnation is similar. What we’re talking about is the event where the God of the universe, who has always been non-physical, became a physical human being. “God with Meat”.
Here’s the Creed of Chalcedon with the incarnation part in italics:
“In agreement, then, with the holy [Nicene] Fathers, we all unanimously teach [Christian] to confess one and the same Son, our Lord Jesus Christ: the same perfect in deity and the same perfect in manness, truly God and truly man, the same of a rational soul and body, consubstantial with the Father according to the deity and the same consubstantial with us according to the manness, like us according to all things except sin; begotten of the Father before the ages according to the deity and in the last days the same, for us and for our salvation, [born] of Mary the Virgin, the God-bearer, according to the manness, one and the same Christ, Son, Lord, Only-begotten, being made known in two natures without confusion, without change, without division, without separation, the distinction of the natures being by no means removed because of the union but rather the property of each nature being preserved and concurring in one person and one subsistence, not parted or divided into two persons but one and the same Son and Only-begotten, God, Word, the Lord Jesus Christ. As the prophets of old [declared] concerning him, and the Lord Jesus Christ himself has taught us, and the [Nicene] Creed of our Fathers has handed down.”
The thing to note about Chalcedon is how they sought to describe the mystery of the incarnation as best they could and as carefully as they could, but in their wisdom refrained from talking about the “how” of the whole thing.
They’re very careful to give full attention to the WHAT of the incarnation, divine nature and human nature, full in themselves and truly united in the one person without any change in either nature. But the question of HOW is completely passed over.
This is a good thing. A number of the Christological heresies we posted about here are a result of people pushing on the “how” question too hard.
Chalcedon sets up the core of the whole thing in outlining the hypostatic union. The hypostatic union is the term for the uniting of two natures or hypostases, divine and human, in the one person of Jesus Christ. Everything else is a thinking out of biblical trajectories from there. Two natures united in the one person without any damage or change being done to either nature in the process. Which is what this sentence is outlining and protecting:
being made known in two natures without confusion, without change, without division, without separation, the distinction of the natures being by no means removed because of the union but rather the property of each nature being preserved and concurring in one person and one subsistence, not parted or divided into two persons but one and the same Son and Only-begotten, God, Word, the Lord Jesus Christ.
That sentence is everything of the incarnation. If you’ve got that then you’ve got the material for everything else.
Two natures. One person. No changing. No remainder.