The man in the synagogue, a place of religion, needed to be delivered.
      And there was in their synagogue a man with an unclean spirit; and he cried out, Saying, Let us alone; what have we to do with thee, thou Jesus of Nazareth? art thou come to destroy us? I know thee who thou art, the Holy One of God Mark 1:23-24.
In Acts, there's a sorcerer named Simon who must apparently was in the revival in Samaria, 8:13 Then Simon himself believed also: and when he was baptized, he continued with Philip, and wondered, beholding the miracles and signs which were done.

       He believed, was baptized and continued with Philip, but in Acts 8:32, Peter said he was in the 'bond of iniquity'....For I perceive that thou art in the gall of bitterness, and in the bond of iniquity.
If a professed Christian betrays truth as Judas did, he certainly opens himself up to satanic possession.
          Luke 22:3, Then entered satan into Judas surnamed Iscariot, being of the number of the twelve.
If a church member lies like Ananias and Sapphira lied in Acts 5, they can become a stronghold of evil desires.
If a person who claims to be a Christian gets into the occult, he/she can become possessed, 1 Timothy 4:1, Now the Spirit speaks expressly, that in the latter times some shall depart from the faith, giving heed to seducing spirits, and doctrines of devils;
The Bible says in Ephesians 5:18, Be filled with the Spirit and in so doing give no place to the devil.

         Those who don't follow this command to be filled with the Spirit, give place to the devil to run their lives.
A professing Christian can open themselves to lust, lying and jealousy.


        2 Timothy 2:24-26, And the servant of the Lord must not strive; but be gentle unto all men, apt to teach, patient,
 In meekness instructing those that oppose themselves; if God peradventure will give them repentance to the acknowledging of the truth;
And that they may recover themselves out of the snare of the devil, who are taken captive by him at his will.
Anger is a spirit and can actually make a person insane.

        It has been recorded that a violent fit of anger caused a woman's body to be paralyzed. There are others who have suffered  strokes resulting from horrible anger.
It is possible for a professing Christian to become possessed with a demon.

        A church woman suffering from the power of the devil was asked how did the evil spirit get into her. The evil spirit answered back that she was at an adult motion picture watching a sex movie. This opened the way for the spirit to enter her. She was out of bounds of God's protection.

                When a person deliberately goes into devil's territory, it is possible to become a victim to whatever the devil offers, even claiming to be a Christian at the time.

Of course, she could not be possessed in her spirit but she was possessed in her body.
James 4:7,  Submit yourselves therefore to God. Resist the devil, and he will flee from you.

           Submit ourselves to God; focus on Him and His Word, praise, sing and rejoice.
           Resist the devil, submitting to God is part of resisting the devil, don't listen or look at his temptations.
           The devil will flee, he doesn't like being around us when we read, praise, sing and rejoice in the Lord.
One cannot be an effective part to two opposite kingdoms.

        Jesus said a man cannot serve two masters. Matthew 6:24, No man can serve two masters: for either he will hate the one, and love the other; or else he will hold to the one, and despise the other. Ye cannot serve God and mammon.

        James, one of the apostles, asked it sweet and bitter water could come from the same fountain. James 3:11, Doth a fountain send forth at the same place sweet water and bitter?
When Jesus was accused of using demonic power to cast out devils, He said a kingdom divided against itself could not stand, Matthew 12:25,  And Jesus knew their thoughts, and said unto them, Every kingdom divided against itself is brought to desolation; and every city or house divided against itself shall not stand: 
In the final commission before Jesus went back to sit on the right hand of the Father in heaven, HIs last instructions were to deliver people who are possessed of devils.

         He did not infer in any way that these devils could hurt believers or could even stand up against them. He told His disciples to cast them out!

                 The Word of God is either true or not true. If we as Christians have authority to cast out demons, we must obey. "Casting out" is an offensive action. This means to take the initiative and be the aggressor.
The Great Commission was the final words spoken by Jesus Christ on the earth during His ministry,
Mark 16:17,  And these signs shall follow them that believe; In my name shall they cast out devils; they shall speak with new tongues; They shall take up serpents; and if they drink any deadly thing, it shall not hurt them; they shall lay hands on the sick, and they shall recover.
When Jesus sent His seventy disciples, these men were not of the same level of teaching as the first twelve, but they were sent by Jesus also. He gave them power not only to heal the sick, but to cast out devils.

         Jesus didn't warn them to protect themselves against demons or instruct them in any particular way to handle evil spirits other than they were to cast them out.

                  This tells us that Christians cannot be possessed of devils or need to fear them; because we have the Holy Spirit in us and they didn't. Jesus hadn't died yet.
Jesus didn't warn his disciples to protect themselves against demon power. And he didn't warn them that they may become possessed or injured while rebuking them.

          Jesus gave them authority over all demonic forces. The Bible doesn't teach anywhere in it that his followers are to fear the devil or of being in danger of personally possessed of demons.
The Christian's position in Christ is answered by Jesus when He sent His disciples [of which we are] out, giving them the power and authority over devils.

              And when he had called unto him his twelve disciples, he gave them power against unclean spirits, to cast them out, and to heal all manner of sickness and all manner of disease, Matthew 10:1.
Believers must place our lives in the hand of God to guide us every day. We don't need to know what is going to happen tomorrow. If we did, we wouldn't have to walk by faith.

         We don't need to be curious about the future. The Word of God tells us all we need to know. If we believe in the Gospel, we are saved and if we don't we are damned, Mark 16:16. When we die, we either go to heaven or to hell.