Has the Son of God always been incarnate?
This post draws on the teaching of Thomas F. (TF) Torrance in explaining that the incarnation (like the creation) was something 'new' to God, though it was purposed by God from all eternity.
"TF strongly and repeatedly affirmed that the incarnation, like the creation, is something 'new' to God. The Son of God was not always incarnate---the human nature Jesus assumed upon his incarnation was a created human nature, which did not exist from eternity. God alone is eternal. This understanding is backed up by the biblical teaching that creation was ex nihilo (out of nothing). There was not a human person prior to creation.
"However, we can and probably should say that God anticipated in some eternal way both the creation and the incarnation. What God did to bring creation and then incarnation into being corresponds to something that is true of the nature and character of God. Perhaps we could say that these acts of God external to the eternal being of God were always a kind of potential, although not a necessity for God to be God.
"All that God does external to his eternal being is consistent with the eternal nature and character of God. He does nothing external to himself that is uncharacteristic of that nature and character. That is because God is trustworthy or faithful and has revealed himself in all his acts towards his creation.
"But because creation and human nature are not divine and not eternal (are not God or emanations of God’s being) they do not and cannot exist eternally. It also means that all God’s acts external are from the freedom of God and the goodness and grace of God. Though they are not necessary at all, they are fitting of God, true to God’s nature and character.
"Of course, the existence of the Son of God as the second person of the Trinity is eternal (i.e. has existed forever). God is forever a Trinity. There never was a time even for God, in eternity, that God was not the Father, the Son and the Holy Spirit in holy communion or oneness of Being.
"Given the biblical teaching that God alone (and nothing else) is eternal and that all else that exists is created by God through the Son (or is a byproduct of what is created) and so is not eternal, we should understand that along with God’s intention to create was his anticipation of the Fall and the whole Trinity’s commitment to redeem the creation through the Son, the one through whom all things have come into being. God was not taken by surprise that redemption was going to be needed and would cost God. God is omniscient and omnipotent and allowed nothing to happen that was not anticipated and had been provisioned for, including costly redemption.
"But God’s relationship with creation (i.e. what is not God) is real and actual---really and actually established and redeemed. God, while remaining God and the Son of God while remaining the eternal Son of God can indeed be present to and really act within created time and space. We cannot exactly imagine how that can be. But we should expect that to be true since we are not God and do not live or even understand God’s own way of being eternal.
"TF in effect says that if the incarnation was eternal, then there really wasn’t a real incarnation at all, a real engagement with time and space, with creation, with that which was not God---it merely appeared to be a real engagement, encounter, assumption."
I'll now add a relevant quote from TF in "Incarnation, the Person and Life of Christ" (bold face added for emphasis):
"What Christ is in all his life and action, in his love and compassion, he is antecedently and eternally in himself as the eternal Son of the Father.... Thus we must say that the whole course of Christ's human life and work has its ground in the action of the eternal God.... [However] this does not mean that the humanity of Jesus is eternal, that it was eternally pre-existent. It does mean that the person is eternal, that his person is not human, but divine. But it also means that the humanity of Jesus was assumed into oneness with the eternal Son and shares eternally in the glory of the only begotten Son of God which he had before the world was created. The doctrine of the hypostatic union asserts a union of two natures in one person. It does not assert the pre-existence and in that sense the eternity of the human nature, for the human nature of Jesus was a creature of God, and in Jesus himself the human nature had no independent hypostasis prior to the incarnation. But we must assert of the humanity of Jesus that it was given hypostasis, reality, real personal being, in the eternal Word, in the eternal Son, in the eternal hypostasis of God the Son.
"On the one hand, therefore, we must say that in the incarnation something altogether new happened, even for God, for God the Son was not always man but he now became man, became a creature, through without ceasing to be God. On the other hand, the relation of the incarnate Son to the Father did not arise within time. The life of Christ on earth was the obverse of a heavenly deed, and the result of an eternal decision, an eternal prothesis which God had purposed in himself from all eternity." (pp. 176-177)
Artwork: Icon of Christ Pantocrator (public domain via Wikimedia Commons).