One of the first lessons that students of physics learn is that “nature abhors a vacuum.” This means that when you try to empty a container of air and whatever else is inside it, then something else will try to fill the void. The same principle applies in the spiritual realm as well.
Anyone who reads the Gospels for the first time might be surprised to learn that Jesus’ worst and deadliest enemies were the most religious and zealous people of his day. He never had a problem with the Roman soldiers who lorded it over the nation of Israel, and he certainly didn’t have any major clashes with the overt “sinners” surrounding him. It’s especially strange when you consider that he'd agree with the Pharisees regarding most of their theology. He would've totally agreed with them about the existence of God, of Satan, of angels, of the literal truth of the Torah, and the certainty of a judgment to come.
We’ll get into more into what problems he had with the Pharisees at a later time. But for now, we get a hint of the major conflict which would result in his murder. They wanted to test him, and in complete unbelief they asked him to perform some public miracle—as if he hadn’t done enough already, but one more miraculous sign would've them convinced.
He condemned them for asking for this, and unfavorably compared them to the people of Ninevah and the Queen of the South, both of which saw what God was doing and responded appropriately. But what’s the point of the last part of this passage?
I wouldn’t discount the literal meaning of what Jesus is saying about spiritual forces, but I really think that this would be beside the point. What did the Pharisees represent? Why did they hate Jesus so much? They're the ultimate example of religious reformation without a real relationship (please pardon the alliteration).
Imagine a person who’s involved in a terribly sinful lifestyle. He comes to his senses and realizes that the path he’s on will only lead to destruction. So he reforms his life: He no longer smokes, drinks, or indulges in sexual immorality. But what’s missing? Christ! Is it possible to reform your life on the outside, without a genuine relationship with the Savior? Of course it is! This would describe millions of Muslims all over the world, for example.
But what happens to religion without Christ? The man so described becomes a target for seven worse demons than he had before, so his situation is even worse than before he cleaned up. Why did this happen? Because nature abhors a vacuum. He supposedly got rid of the worst sins in his life, but Christ didn’t come in to fill the void, so something else-- far worse--came in instead.
Devotion to Christ is the most wonderful thing in the world. In fact, it’s what we were created for. But religion without Christ is worse than useless—it’s the most destructive force in the history of mankind, and so of course it’s the most useful tool in the Enemy’s hands. So have you fallen into the trap? Do you have religion or a relationship?
Lord Jesus, you know what I want. I will settle for nothing less than you. Nothing is worth pursuing anyway.