The second day of creation, the day the firmament called heaven is made, is the only day about which it was not said, “it was good.”

The reason that God left “it was good” off of the second day is that the firmament is the place where Satan, the fallen angels, and demons live.

In Eph. 6:10-18, we are instructed to “put on the whole armour of God,” because we are in a spiritual warfare “against principalities, against powers, against the rulers of the darkness of this world, against spiritual wickedness in high places,” (v.13).

In Is. 24:21, we find that there are powers that are higher than the kings and they are called the “host of the high ones that are on high.”
The devil that leads them is called “the prince of the power of the air” in Eph. 2:2, and he rules from an invisible mountain from which all the kingdoms of this world may be seen simultaneously (Lk. 4: 5-8).

From Dan. 10, we can see that the devil has “princes” over kingdoms that fight with the angels of God, and the outcome of their warfare is seen in the rise and fall of the kingdoms of the earth. For instance, in Dan. 10:13, an angel (or the pre-incarnate appearance of Christ) and Michael, the archangel, fight with “the prince of the kingdom of Persia.” Then in v.20, we find that the “prince of Persia” is defeated and the “prince of Grecia shall come.”

We know from the Bible and history that Darius the Median defeated Belshazzar the Babylonian in 538 BC to begin the Persian Empire (Dan. 5:1,31). Afterward, Cyrus king of Persia (Dan. 10:1) ruled this empire. The Persian Empire continued until Alexander the Great led the Macedonian and Greek armies to conquer them between 336 and 323 BC, thus fulfilling the prophecy given to Daniel about the princes. The Greeks had beaten the Persians.

In the end, Michael and his angels will defeat the devil and his angels and throw them out of the firmament called heaven and cast them into the earth (Rev. 12:7-9). At that time, the kingdoms of the earth will become the kingdoms of Jesus Christ (Rev. 11:15).