Revelation 21:17,18

And he measured the wall thereof That is, Lowman thinks, the height of the wall; one hundred and forty-four cubits The square of twelve: about seventy-two yards high, according to the lesser cubit, or about eighty-six yards according to the greater, a height sufficient to express the most perfect security against all attempts of any surprise by an enemy. Doddridge understands these cubits of the thickness of the wall, with the same view, namely, to signify the great strength of the city, and that it might defy all assailants. According to the measure of a man A measure common among men; that is, of the angel For such was the measuring-rod, made use of by the angel. And the building of the wall was of jasper The wall appeared to be built with unparalleled strength and magnificence, not of brick, or squared and polished stones, but of some precious stone, as solid, firm, and beautiful as a jasper. And the city was of pure gold Namely, its houses and other buildings, separate from the wall; like unto clear glass Or crystal. It seems it is the city in general, and not the gold, which is represented as shining like glass or crystal. It is not easy to understand how pure gold should shine like crystal: but a city adorned with crystal, set in gold, may easily be supposed to shine in that manner.