Over the past couple of years I’ve been learning a lot about the spiritual realm, that place within creation that is inhabited by spiritual beings. Of course, we humans live in the physical realm, the creation of which is described in Genesis 1, but we are unique among physical creatures because we have a spiritual element — something that we have come to call a spirit. (We’re so creative!) The Bible tells us that, because of this, we have a certain amount of access to the spiritual world. In fact, it seems as though God’s plan was, and still is, for humans to be the link between, and even the rulers of, a new, combined spiritual and physical universe. If you’re interested in this sort of thing, I strongly recommend you check out the work of Dr. Michael Heiser. You can read my review of his book The Unseen Realm here.
A spiritual stronghold is a mental or emotional space controlled by our spiritual enemy.
Not all of the spiritual beings liked God’s plan to make human beings the rulers of both realms (ruling alongside God himself, of course), and so they sought to corrupt humans. I think that these spiritual beings wanted to both prove our unworthiness for the role, while at the same time showing how strong, wise, and qualified they were to rule the universe. Regardless of their intentions, their plan succeeded, and we have all lived in what the Bible calls sin ever since. Humans are in an interesting position here, because we are both actors in a spiritual war and the objects of that war. We are both soldiers and the battleground, and because of this sin, we don’t fight on the side of the good guys nearly often enough. Fortunately for us, God has fought back against these dark spiritual beings to redeem and reclaim us, which is what the crucifixion and resurrection of Jesus were all about. Now that these forces of evil know that God will ultimately win, their goal is to bring as many of us into their condemnation as possible.