For effectiveness in casting away demons(not necessary possessed in persons), it becomes necessary to have some knowledge about spiritual powers, principalities and wicked things in the spiritual places that have a lot of effect on mens lives.The rulers of this world are attached to the sons of darkness, in spirit. The wicked are the vessels of wrath and this is why you do not cast out every spirit sensed. The word wicked is actually more in reference to the demon than to the men so possessed. This possession gets more harder to separate with time. This are very territorial spirits in such circumstances. These spirits are rulers, and their authority is not just over men but also over the powers of darkness, which are the works of wickedness(1 Cor 6:9-10). Just like the power of God is hidden in His character, the powers of the devil are in His character, wickedness. Rulers, in their appointed hosts, are actually beneficial to them, in an ungodly way, through acts of witchcraft/wickedness in the high(spiritual places). This is why witches will boast with statements like "good things always follow me." Trouble comes when the possessed is a vessel appointed for the glory of God, then you have torment, abnormal anxiety or fear which is one test of their presence. Rulers use their powers, from inside or from without, to fight the power of God. Remember the power of God is in His Character - love, joy, patience, peace, meekness, long-suffering...righteousness, peace and joy is the kingdom of God. This is a true mark of the presence of God in ones life. This negative influence is what is witchcraft. Forget the scary tales of the village witches which are only intended to cover up the truth besides instilling unreasonable fear.
