Deliverance is NOT for non-believers
The truth is that if we went about casting demons out of non-believers, then we would be ignoring some very important things that Jesus had to say about the deliverance ministry. Consider these passages in scripture:
"But he answered and said, It is not meet to take the children's bread, and to cast it to dogs."
Matthew 15:26
In the above verse, Jesus was speaking with a woman outside covenant with God, concerning casting a demon out of her daughter. Jesus made it very clear that this ministry was not intended for those outside covenant with God.
"When the unclean spirit is gone out of a man, he walketh through dry places, seeking rest, and findeth none. Then he saith, I will return into my house from whence I came out; and when he is come, he findeth it empty, swept, and garnished. Then goeth he, and taketh 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. Even so shall it be also unto this wicked generation."
Matthew 12:43-45
In the above passage, Jesus was making it very clear that if we cast a demon out of somebody who rejects Jesus as their Lord and savior, then we are setting that person up for a disaster.
One of the serious flaws in the idea of casting demons out of non-believers is that the demons have a right to be there, and unless a person accepts Jesus, that right cannot be removed or nullified. The Bible tells us that when our sins are forgiven, the unclean spirits are stripped of their legal grounds in our lives:
"And you, being dead in your sins and the uncircumcision of your flesh, hath he quickened together with him, having forgiven you all trespasses; Blotting out the handwriting of ordinances that was against us, which was contrary to us, and took it out of the way, nailing it to his cross; And having spoiled principalities and powers, he made a show of them openly, triumphing over them in it."
Colossians 2:13-15
Unfortunately, a non-believer cannot have their legal grounds removed, therefore, attempting to drive out a demon can be a dangerous scenario.