We know the great strength, purity and transparency of crystalline rock that was made by the congealing of the waters. It is established that the firmament is in the midst of the waters, for we understand that waters were placed beneath the firmament and in the air and the land and we are taught about the placement of these waters above it by the authority of this Scripture passage and by the words of the prophet who said, “Spreading out heaven like a tent, you cover your chamber with waters.” It is in agreement then that the starry heaven was firmly set in the midst of the waters, and this does not prevent the belief that it was made from these waters. “Described in these verses is the creation of our heaven in which the stars are fixed. Below is an extract from Bede the Venerable’s commentary (how do you even get a name like that!?!): It plainly meant there was a solid barrier holding up water.

Untroubled by the modern fooleries of science, ancient commentators didn’t pretend the firmament meant expanse, or air or some similar nonsense.

Firmament of heaven