And God said, Let there be a firmament in the midst of the waters, and let it divide the waters from the waters. Genesis 1.6.
Concerning the Six Days of work, God pronounced each day’s work as good except the second day. Did God forget? Not at all, for what He says or does not say is equally full of meaning. The Scriptures are God-breathed, word for word. He did not pronounce the second day’s work good because the firmament or air is somewhat related to Satan. Is not Satan "the prince of the powers of the air" (Eph. 2.2)? Seeing that this firmament would be the habitation of Satan and his evil spirits, God did not sum up this day’s work as being good. The air thus becomes the headquarters for the kingdom of darkness. For this reason, while we are meeting or praying, we need to ask God to clear the air by means of the precious blood of our Lord so that we may not be oppressed by the enemy.