Selection from Apocalypse Explained ~ Emanuel Swedenborg
As the heavens are divided into two kingdoms, namely, into a celestial kingdom and a spiritual kingdom, so are the hells divided into two dominions opposite to those kingdoms. The dominion opposite to the celestial kingdom is called devilish, and the dominion opposite to the spiritual kingdom is called infernal. These dominions are distinguished in the Word by the names Devil and Satan.There are two dominions in the hells, because the heavens and the hells are opposite to each other; and opposite must fully correspond to opposite that there may be equilibrium. For the existence and subsistence of all things, both in the natural world and in the spiritual world, depend upon an exact equilibrium between two activities that are opposite; and when these act against each other manifestly, they act by forces, but when not manifestly they act by endeavors [conatus].
By means of equilibriums all things in both worlds are preserved - without this all things would perish.In the spiritual world the equilibrium is between good from heaven and evil from hell; and thus between truth from heaven and falsity from hell. For the Lord continually arranges that all kinds and species of good and truth in the heavens shall have opposite to them in the hells evils and falsities of kinds that correspond by opposition; thus goods and truths from a celestial origin have for their opposites evils and falsities that are called devilish; and in like manner goods and truths from a spiritual origin have for their opposites evils and falsities that are called infernal.
The cause of these equilibriums is to be found in the fact that the Divine goods and the Divine truths that the angels in the heavens receive from the Lord, the spirits in the hells turn into evils and falsities. All angels, spirits, and men are kept by the Lord in equilibrium between good and evil, and thus between truth and falsity, in order that they may be in freedom; and thus may be led from evil to good and from falsity to truth easily and as if by themselves, although in fact, they are led by the Lord. For the same reason they are led in freedom from good to evil, and from truth to falsity, and this, too, as if by themselves, although the leading is from hell.
(Apocalypse Explained 1043)