And God made the firmament, and divided the waters which were under the firmament from the waters which were above the firmament: and it was so.
All Commentaries on Genesis 1:7 Go To Genesis 1
Augustine of Hippo
AD 430
The waters were divided so that some were above the firmament and others below the firmament. Since we said that matter was called water, I believe that the firmament of heaven separated the corporeal matter of visible things from the incorporeal matter of invisible things. .
