In reading your answer to Understanding Luke 11:24-26 you point out that the demons begged Jesus to allow them to enter the pigs after they were driven out of the man. Does this mean that demons need God’s permission to enter or re-enter a human? I know, as a Born Again Believer that has accepted Jesus and invited Him to reside within me, I cannot be demon possessed. But what about others? Are demons free to inhabit people or do they need to seek God’s permission first?
Because the whole world is under the control of the evil one (1 John 5:19) demons don’t need God’s permission to inhabit non-believers. The reason the demons asked to be allowed to inhabit a herd of pigs in Mark 5:1-17 was to avoid going to a place of torture which is where I believe Jesus would have sent them otherwise (Mark 5:7). When the pigs ran down the hill and drowned themselves in the Sea of Galilee the demons must have wound up in the place of torture after all. Otherwise Jesus would have been setting them free to afflict others as if they’d never gone into the pigs.