Let us quote correctly. The apostles could not cast out the demon of a boy who threw himself on the fire. Jesus did and said some spirits could only be cast out with prayer and fasting ie spiritual preparation. Mark 9:29
Matt 8:28-32
Jesus cast demons out of the men in the tombs into the pigs, and no one repented.
When he arrived at the other side in the region of the Gadarenes,[SUP]
[c][/SUP] two demon-possessed men coming from the tombs met him. They were so violent that no one could pass that way. [SUP]
29 [/SUP]“What do you want with us, Son of God?” they shouted. “Have you come here to torture us before the appointed time?” [SUP]
30 [/SUP]Some distance from them a large herd of pigs was feeding. [SUP]
31 [/SUP]The demons begged Jesus, “If you drive us out, send us into the herd of pigs.”
[SUP]
32 [/SUP]He said to them, “Go!” So they came out and went into the pigs, and the whole herd rushed down the steep bank into the lake and died in the water.
So your proposition is wrong. I suggest you write down your beliefs and then look at the passages you claim that support you ideas and see if you are right. Your simple answer to me was not, which is not a good start.
The other point about the boy who was thrown into the fire, it was obvious he was possessed, it was just a problem of getting him free of it. I was making the point if you did not know if a spirit was involved, it probably was not.