Theology set in stone

For those who don't read Tim Enloe's blog, here is a quote I shared with him from a book I'm reading:
In Damascus the [Muslims] built a mosque that was a veritable wonder. An Arab traveler has described it as it was at this time.
Nowhere else is such magnificence. Its outer walls are of squared stones, and crowning the walls are splendid battlements. The columns supporting the roof of the mosque consist of black polished pillars in a triple row. In the center of the building is a great dome. Round the court are lofty colonnades above which stand arched windows, and the whole area is paved with white marble. For twice the height of a man the inner walls of the mosque are faced with variegated marbles, and above this, even to the ceiling, are mosaics of various colors and gold, showing figures of trees and towns and beautiful inscriptions, all most exquisitely worked. The capitals of the columns around the court are all of white marble, while the walls that enclose it are adorned in mosaics.
Both within the mihrab and around it are set cut agates and turquoises of the size of the finest stones that are used in rings. On the summit of the dome of the mosque is an orange and above it a pomegranate, both in gold. Before each of the four gates is a place for ablution, of marble, wherein is running water and fountains which flow into great marble basins....The Kalif al Walid spent thereupon the revenues of Syria for seven years, as well as eighteen shiploads of gold and silver.
But within the mosque over a sealed entrance that had been the door of the great Roman basilica upon the foundations of which the mosque had been built, remained an inscription worn by time--"Thy kingdom, O Christ, is an everlasting kingdom, and thy dominion endureth through all generations." [Harold Lamb, The Flame of Islam (Garden City, NY: Doubleday and Co., Inc., 1953), pg. 9]