As a student at a self-identified fundamental Bible college and then seminary, I was intrigued at the warnings sounded about Karl Barth. It was not the normal five alarm cry of, “Heretic!” There was hemming and hawing. There was shuffling of feat. Of course such nervous warnings to stay away from Barth only served to pique my interest and drove me to him. Like an intruder at a speakeasy I found out what all the fuss was about. “No one ever spoke like this man!” Barth is dangerous to fundamentalists because when Barth is right one can only think that no theologian has ever been more right. “The Miracle of Christmas” is such a place.
We do not come to know the Virgin Birth in relation to other knowledge. There is no category to fit it into. “It becomes the object of our knowledge by its own power and not by ours.” We do not come to accept the Virgin Birth as God’s Pythagorean Theorem. It is not something we build up to. It is not something we reason toward.
In acknowledgement and confession of the inconceivableness of this reality we describe it as the act of God himself, of God completely and solely. If we speak of it in any other way, if we deny its inconceivability, if we think that by our statements we are speaking of something within the competence of our experience and thought which we can encounter and master, we are speaking of something different from the dogma and from the Scripture expounded in the dogma.
How can Barth make such an assertion? How can the incarnation, an act of revelation, be at its core inexpressible and unknowable? It is because of his biblical understanding of what the Virgin Birth is: “It is a sign set up immediately by God, and can only be understood as such.”
With Isaiah 7 in mind, the Virgin Birth is a sign to the proud. It is a sign to all the arrogant that know too much to submit to the Lord’s command. In such a context should we really expect the Virgin Birth to be something explainable? Something understandable? “The virginity of Mary in the birth of the Lord is the denial, not of man in the presence of God, but f any power, attribute or capacity in him for God.”
King Ahaz lives on. He fills many a pulpit and many a pew. He is content with God at a distance. He dares not ask the Lord for a sign, because he wouldn’t believe it anyway. He is not interested in the miracle of Christmas. He is not interested in the mystery of Christmas.
The man Jesus of Nazareth is not the true Son of God because he was conceived by the Holy Spirit and born of the Virgin Mary. On the contrary, because He is the true Son of God and because this is an inconceivable mystery intended to be acknowledged as such, therefore He is conceived by the Holy Spirit and born of the Virgin Mary. And because He is thus conceived and born, He has to be recognized and acknowledged as the One He is and in the mystery in which He is the One He is.
 Karl Barth, Church Dogmatics, vol. 1 part 2, The Doctrine of the Word of God (Edingurgh: T &T Clark, 1970), 172-202.