Can Demons Re-possess a Person?
It has now become a common practice in many ministries to cast out demons during their Services. We can see the possessed individuals powerfully delivered, and their conditions often change instantly!
But is it possible for a demon to re-enter a person after it is cast out? Of course it is! The Bible has already told us that not only is it possible, but the condition of the person can become even worse than before!
When the unclean spirit is gone out of a man, he walks through dry places, seeking rest, and finds none. Then he says, I will return into my house from where I came out; and when he comes, he finds it empty, swept, and garnished. Then he goes, and takes with himself seven other spirits more wicked than himself, and they enter in and dwell there; and the last state of that man is worse than the first. Matthew 12:43-45
We can see that after a demon is cast out, it has nowhere to go! Therefore, its first choice is often to return to his "old house". If the person delivered continues to sin, and does not repent nor invite the Holy Spirit to abide in him, the demon can easily re-enter. Probably in order to strengthen itself, it will bring more demons more wicked than itself in the hope that it will not be cast out again! Of course, condition of the possessed person (who now has even more demons) becomes worse than before
Example of a Demon Re-possessing a Person
It is recorded in the Bible that Lord Jesus once cast out a multitude of demons called "Legion". They were driven into a herd of swines which then went violently down into the water and got drowned.
In the Book of Luke, this incident was recorded in greater details, and we were told that the man had actually been delivered by Jesus before! It is clear then that the demons had returned and re-possessed the man.
When He (Jesus) went forth to the land, there met him out of the city a certain man, which had devils long time, and wore no clothes, neither abode in any house, but in the tombs. For He had commanded the unclean spirit to come out of the man (before). Luke 8:28-29
Was the condition of the man worse than before? We were told that before demons were cast out for the first time, the man was driven by the devil into the wilderness, and was so strong that he broke the chains and fetters that were used to bind him (Luke 8:29). However, after the demons re-entered him, he wore no clothes, did not stay in any house, but abode in tombs (Luke 8:28). In addition, we know that the number of demons in him was MANY, which was why they called themselves "Legion".
Apparently the man got smart this time, and asked to stay with Jesus. He probably already realized that demons can actually re-possess him! Even though Jesus did not consent to his request, he obediently followed the commandment of Jesus to witness what God has done for him. Of course we now know that witnessing is also a way to keep the demons out, as written in Revelations 12:11, "And they overcame him (devil) by the blood of the Lamb, and by the word of their testimony."
Now the man out of whom the devils were departed besought Him (Jesus) that he might be with Him: but Jesus sent him away, saying, Return to your own house, and show how great things God has done unto you. And he went his way, and gave word throughout the whole city how great things Jesus had done unto him. Luke 8:38-39
What Must We Do After Demons Have Been Cast Out?
Lord Jesus already gave us solemn warnings that after our deliverance from demonic influence, we must SIN NO MORE!
After Jesus healed a man who had been sick for 38 years, He gave him a warning specifically that something worse may happen to him if he continues to sin. (John 5:5-16)
See, you are well and strong; do no more sin for fear a worse thing comes to you." John 5:14
Jesus did not explain why, but we know now that if a man is not determined to separate himself from demonic influence, it is very possible for the demons to do harm to him again. When Jesus let go of the woman who committed adultery, He also said the same thing, "Neither do I condemn you. Go, and sin no more." (John 8:11)