All this indescribable thing that we call the Christmas atmosphere only hangs in the air as something like a lingering fragrance or fading vapour from the exultant explosion of that one hour in the Judean hills nearly two thousand years ago. But the savour is still unmistakable, and it is something too subtle or too solitary to be covered by our use of the word peace. By the very nature of the story the rejoicings in the cavern were rejoicings in a fortress or an outlaw's den; properly understood it is not unduly flippant to say they were rejoicings in a dug-out. It is not only true that such a subterranean chamber was a hiding-place from enemies; and that the enemies were already scouring the stony plain that lay above it like a sky. It is not only that the very horse-hoofs of Herod might in that sense have passed like thunder over the sunken head of Christ. It is also that there is in that image a true idea of an outpost, of a piercing through the rock and an entrance into an enemy territory. There is in this buried divinity an idea of undermining the world; of shaking the towers and palaces from below; even as Herod the great king felt that earthquake under him and swayed with his swaying palace.