Genesis 1:6-7

Amplified Bible, Classic Edition

⁶ And God said, Let there be a firmament [the expanse of the sky] in the midst of the waters, and let it separate the waters [below] from the waters [above].

⁷ And God made the firmament [the expanse] and separated the waters which were under the expanse from the waters which were above the expanse. And it was so.