Luke 11:24-26 (ESV)
"When the unclean spirit has gone out of a person, it passes through waterless places seeking rest, and finding none it says, 'I will return to my house from which I came.'  And when it comes, it finds the house swept and put in order.  Then it goes and brings seven other spirits more evil than itself, and they enter and dwell there. And the last state of that person is worse than the first."
I read this and I think of Jesus telling the Pharisees : “ Woe to you, scribes and Pharisees, hypocrites! For you travel across sea and land to make a single proselyte, and when he becomes a proselyte, you make him twice as much a child of hell as yourselves. “ (Matthew 23:15 (ESV)
It is the Christless Christianity, a completely human repentance that is too often preached instead of Christ. True repentance centers on the first commandment, it realizes that all sin stems from unbelief, unfaith. Therefore true repentance, repentance as the Bible talks of it, is faith and faith in the forgiveness of sins in Jesus Christ. This repentance comes with water in the form of baptism, a gift from God.
But this isn’t repentance as most think of it. They drive out the demons. They send them away and clean up their acts as far as outward behavior. Half the time it isn’t even about sin, but behavior society has deemed crude. But without forgiveness, without faith in Christ, it is not repentance. What you have is a a man who has become twice the child of hell he was before he started. The demons come back, and they invite their friends. There is no lord at home.
But with baptism, with faith in the forgiveness of sins offered there in, being joined into Christ’s death and raised with him to walk in the newness of life, ah now the home has been shut to the demon, he will pass through the waterless places, but he will not return to those who have been passed through the water.