“And they brought the boy to him. And when the spirit saw him, immediately it convulsed the boy, and he fell on the ground and rolled about, foaming at the mouth. And Jesus asked his father, “How long has this been happening to him?” And he said, “From childhood. And it has often cast him into fire and into water, to destroy him. But if you can do anything, have compassion on us and help us.”” (Mark 9:20–22, ESV)
Mark 9.14-29 is an encounter that Jesus and his disciples have with some argumentative scribes, a crowd of people, and an unnamed father who has a son that is under the influence of an unclean spirit. The only thing that we learn about how the child came under the influence of an unclean spirit [or a demon] is that it had been a problem “from childhood.” We are not told how the demon came to influence the boy, or why, just when. This seems to be the pattern throughout the gospels. We see many people that have come under the influence of the demonic, but we are never told how they came under that influence.
We experience the same thing in our day. While we do not see a lot of overt demonic behavior in western culture [due, we suspect, to the fact that the Devil has more than one way to reach his aims] the occult and the demonic is still a huge factor in third world cultures and actually a growing factor in western culture as we cast off more and more of Judeo-Christian norms. We do know that one way to come under the influence of the demonic is through dabbling in the occult. We do not know much beyond that about how an individual person comes under the influence of a demon or demons.
Do not miss the aim of the demonic. The father says that the unclean spirit has often cast him into fire and into water, to destroy him. This is universally the aim of the demonic world: destruction. They are not out to help; they have no desire to build people up and make them into better human beings; when they work and whenever they work it is always for the purpose of destroying and tearing down, never for building up. This does of course, make sense. Since the Devil and his minions oppose God, then it would follow that their one unalterable purpose is to try to tear down where God is building up, to destroy where God creates, and to enslave where God offers freedom from slavery.
What is the follower of Christ to do in light of the demonic? Paul explains:
“For we do not wrestle against flesh and blood, but against the rulers, against the authorities, against the cosmic powers over this present darkness, against the spiritual forces of evil in the heavenly places. Therefore take up the whole armor of God, that you may be able to withstand in the evil day, and having done all, to stand firm.” (Ephesians 6:12–13, ESV)
We are called to stand firm against the spiritual forces of evil in the heavenly places. We stand firm by taking on the whole armor of God.