The Bible

Genesis 1:7

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.

The Bible

Genesis 9:6

⁶ Whoso sheddeth man's blood, by man shall his blood be shed: for in the image of God made he man.

Commentary

Firmament

The firmament of heaven represents mutual love. The firmament, as in Genesis 1, signifies the internal man.

(References: Arcana Coelestia 24)