“No one can doubt that the Christianity of the New Testament is supernaturalistic through and through. Whether we have regard to the person of Jesus or to the salvation he brought to men, the primary note of this Christianity certainly is supernaturalism. He who walked the earth as its Lord, and whom the very winds and waves obeyed; who could not be holden of the grave, but burst the bonds of death and ascended into the heavens in the sight of man: he who now sits at the right hand of God and sheds down his gift of salvation through his Spirit upon the men of his choice – it were impossible that such a one should have entered the world undistinguished among common men. His supernatural birth is given already, in a word, in his supernatural life and his supernatural work, and forms an indispensable element in the supernatural religion which he founded.
It would no doubt be difficult – or impossible, if you will – to believe that a natural Jesus had a supernatural origin; or, going at once to the root of the matter, that a natural “salvation” requires a supernatural Redeemer. Much of the Christianity about us today is distinctively, and even polemically, to use von Hartmann’s term, “autosoteric”; and he who feels entirely competent to save himself finds a natural difficulty in believing that God must intervene to save him. I fully agree with the adherents of this “autosoteric” Christianity, that from their point of view a supernatural birth for Jesus would be devoid of significance, and therefore incredible. They should with similar frankness allow to me, I think, that to the Christianity of the New Testament, on the other hand, just because it stands as the opposite pole to their “autosoteric Christianity,” the supernatural birth of Jesus is a necessity.”
– B.B. Warfield (1851–1921), Works, Vol. III, p. 451-452