Genesis 1:7
"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."Genesis 1:7 (KJV)
Context from Genesis 1
5
And God called the light Day, and the darkness he called Night. And the evening and the morning were the first day.
6
And God said, Let there be a firmament in the midst of the waters, and let it divide the waters from the waters.
7
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.
8
And God called the firmament Heaven. And the evening and the morning were the second day.
9
And God said, Let the waters under the heaven be gathered together unto one place, and let the dry land appear: and it was so.