Fourth Sunday of Advent, December 23, 2018
But why is it precisely God the Holy Spirit who is named here?
The answer to this question follows from what we have to learn from Holy Scripture of the significance of this the third person or mode of God’s being for the act of divine revelation or reconciliation, understanding it in terms of what the Church has expressed and laid down as right knowledge of Scripture in its dogma of the three-in-oneness of God and particularly in its dogma of the Holy Spirit.
The Holy Spirit is God Himself in His freedom exercised in revelation to be present to His creature, even to dwell in him personally, and thereby to achieve his meeting with Himself in His Word and by this achievement to make it possible.
Through the Holy Spirit and only through the Holy Spirit can man be there for God, be free for God’s work on him, believe, be a recipient of His revelation, the object of divine reconciliation.
In the Holy Spirit and only in the Holy Spirit has man the evidence and guarantee that he really participates in God’s revealing and reconciling action.
Through the Holy Spirit and only through the Holy Spirit does God make His claim on us effective, to be our one Lord, our one Teacher, our one Leader.
In virtue of the Holy Spirit and only in virtue of the Holy Spirit is there a Church in which God’s Word can be ministered, because it has the language for it, because what it says of revelation is testimony to it and to that extent the renewal of revelation.
The freedom which the Holy Spirit gives us in this understanding and in this sphere–gives, so far as it is His own freedom and so far as He gives us nothing else and no less than Himself–is the freedom of the Church, of the children of God.
It is the freedom of the Holy Spirit and in the Holy Spirit that is already involved in the incarnation of the Word of God, in the assumption of human nature by the Son of God, in which we have to recognize the real ground of the freedom of the children of God, the real ground of all conception of revelation, all lordship of grace over man, the real ground of the Church.
The very possibility of human nature’s being adopted into unity with the Son of God is the Holy Ghost.
Here, then, at this frontal point in revelation, the Word of God is not without the Spirit of God.
And here already there is the togetherness of Spirit and Word.
Through the Spirit it becomes really possible for the creature, for man, to be there and to be free for God.
Through the Spirit flesh, human nature, is assumed into unity with the Son of God.
Through the Spirit this Man can be God’s Son and at the same time the Second Adam and as such “the firstborn among many brethren” (Romans 8:29), the prototype of all who are set free for His sake and through faith in Him.
As in Him human nature is made the bearer of revelation, so in us it is made the recipient of it, not by its own power, but by the power conferred on it by the Spirit, who according to 2 Corinthians 3:17 is Himself the Lord.
The specific mention of the Holy Spirit as a more precise determination of the sign of the Virgin birth is obviously significant in a twofold sense.
In the first place, it refers back the mystery of the human existence of Jesus Christ to the mystery of God Himself, as it is disclosed in revelation–the mystery that God Himself as the Spirit acts among His creatures as His own Mediator, that God Himself creates a possibility, a power, a capacity, and assigns it to man, where otherwise there would be sheer impossibility.
And the mention of the Holy Ghost is significant here in the second place, because it points back to the connection which exists between our reconciliation and the existence of the Reconciler, to the primary realization of the work of the Holy Spirit.
For it is on this ground that the same work, the same preparation of man for God by God Himself, can happen to us also, in the form of pure grace, the grace manifested in Jesus Christ, which meets us and is bestowed upon us in Him.
from Karl Barth, “The Miracle of Christmas”, Church Dogmatics I.2, page 198-200