What about if a believer strays and messes with witchcraft or something like that and wants for some bizarre reason to rebel and go against God?
Im not sure why Im finding this interesting at the moment. Ive heard like on the 700 club ex witches and stuff and they explained how they found it honoring but scary to have a demon in them. I remember the story in the Bible where Jesus and his disciples went to that island and there was a man there possessed by multiple demons and then Jesus casted them out into pigs and they jumped off the cliff.....but Im curious to how and why those demons were in that man. I know no one knows the answer, but its things like that Im curious to know.
If a believer strays, they would still have the Holy Spirit dwelling in their spirit/soul. (Sealed unto the day of redemption). So then they could not be possessed because they would be co-habitating with the Holy Spirit. The Holy Spirit is God.... God the Spirit.. so if a demon could possess a saved individual they would be over powering God Himself.
Do you really think that is possible?
As for the man who had demons cast from him to the swine, I am not sure what scripture says about how he got them. He had an 'unclean' spirit, dwelt among the tombs, no one was able to bind him anymore- he had torn apart the chains. He was constantly among the tombs, gashing himself and screaming.
Maybe this man was trying to end his life because of his tormented spirit, but could not due to the possession, being prevented from ending his life.
Jesus was the only one who had complete power to convict this man and then cast out the demons.
Anyway, it's important not to focus so much on Satan and his minions and more on God's power and grace. Focusing on what overcomes evil leads to bearing fruit rather than focusing on the evil.