The virgin birth cannot be considered in abstraction from the triumphant consummation of Christ’s life in his resurrection, for it is there that the mystery of his person is revealed. In fact the birth of Jesus of the virgin Mary and the resurrection of Jesus from the virgin tomb (‘where no one had ever yet been laid’) are the twin signs which mark out the mystery of Christ, testifying to the continuity and the discontinuity between Jesus Christ and our fallen humanity.
The incarnation is not only a once and for all act of assumption of our flesh, but the continuous personal union of divine and human nature in the one person of the incarnate Son, a personal union which he carried all the way through our estranged estate under bondage into the freedom and triumph of the resurrection.
Thus it is in the resurrection that we see the real meaning of the virgin birth, while the virgin birth has much to tell us about the resurrection. These are then the twin signs testifying to the miraculous life of the Son of God within our humanity, the one at the beginning and the other at the consummation of the earthly life of Jesus.
— Thomas F. Torrance Incarnation: The Person and Life of Christ (Downers Grove, Ill.: InterVarsity Press, 2008), 96
(HT: Of First Importance)