It was the Council of Chalcedon in the mid-5th century that hammered out the Christology (‘speech about Christ’) that became orthodox for Christians everywhere. According to the Chalcedon formula, the best way to refer to Jesus Christ is as ‘the God-Man.’
Makes him sound like a super-hero, I know, which is unfortunate since that’s the last thing the Church Fathers were after. Their formula was just the best way to insure that latter day Jesus-followers like us didn’t forget that Jesus the Son is true God and true Man, without division or confusion between his two natures.
He is fully both God and Man.
And, in a latent sense, he has always been both.
In other words, the Son who is the 2nd Person of the Trinity was always going to be the eternal Son who became incarnate and thus the son of somebody like Mary.
According to Maximus the Confessor– indisputably one of the greatest minds in the history of the faith:
The Chalcedonian formula necessitates we affirm that the incarnate Logos is the elect unifier of all things which are separated.
Whether- and this is key- by nature or by sin.
We all know Sin separated us from God.
That’s an every Sunday, altar call kind of presumption- so much so, in fact, that we neglect to remember or notice that less nefarious but even more fundamental fact separates us from the infinite.
That the son of Mary is the eternal-eventually-to-become-incarnate Son of the God we call Trinity shows, says Maximus, that the Logos is the One through whom all things physical and spiritual, infinite and finite, earthly and heavenly, created and uncreated would be united and made one.
Union, says Maximus, was God’s first and most fundamental aim.
At-onement of a different sort.
Jesus isn’t made simply to forgive or die for our sins. Because if Christ is the God-Man, then everything goes in the other direction.
Jesus isn’t made for us; we were made for him. By him.
We are the ones with whom, through him, God wants to share God’s life.
It’s not that Jesus is the gift God gives us at Christmas; it’s that at Christmas we finally discover that we’re the gift God has given to himself.
We’re the extravagance the superabundant love of Father, Son and Spirit gratuitously seek to share with one another.
Jesus is the reason for the season, but one of the reasons for Jesus is that before the stars were hung in place, before Adam sinned or Israel’s love failed God’s deepest desire is, was and always will be friendship.
(Of course Robert Jenson, by way of Barth, argued that the preexistence of the Son in the Trinity implies the Incarnate Son’s cross- that Jesus was born to die, that all was made alive knowing that it would have to be made alive again through his death and resurrection-but that’s a question for another day.)