Evil spirits are the enemies of Christ and of man. The Bible teaches that sin originates from the devil (1John 3:8). Only when a person distances himself from God by a sinful way of life and plunges into the darkness of disbelief and the passions he is inviting evil spirit in his life. Scripture speaks repeatedly of Satan being the father of lies and a deceiver (John 8:44; 2 Thessalonians 2:9) and he disguises himself an angel of light. Which means that even if something appears to be good in all aspects of it, yet in the end doesn't glorify God, then it's from the devil disguising himself as an angel.
Evil spirits are from God their purpose is to destroy that which is already doomed to destruction. They have a role to play in accomplishing God's will and purpose in this earth so that as many people as possible can come to know Christ. In Psalm 78:49, God judged Israel "by sending evil angels among them." In Judges 9:23, "God sent an evil spirit between Abimelech and the men of Shechem." In 1Kings 22:22, God sent a "lying spirit" in the mouth of the false prophets to send Ahab to his death. When God removes His protective hand, he often turns the person over to Satan for destruction or to an evil spirit for torment.
The Bible has many names for evil spirits:
Deaf and dumb spirit (Mark 9:17-29)
Evil spirit (Luke 7:21; Acts 19:12-13)
Familiar spirit (I Samuel 28:7)
Foul spirit (Mark 9:25)
Lying spirit (II Chronicles 18:20-22)
Perverse spirit (Isaiah 19:14; Romans 1:17-32)
Seducing spirit (I Timothy 4:1)
Spirit of an unclean devil (Luke 4:33)
Spirit of antichrist (I John 4:3)
Spirit of bondage (Romans 8:15)
Spirit of death (I Corinthians 10:10, 15:26)
Spirit of divination (Acts 16:16)
Spirit of error (I John 4:6)
Spirit of fear (II Timothy 1:7)
Spirit of haughtiness (Proverbs 16:18-19)
Spirit of heaviness (Isaiah 61:3)
Spirit of infirmity (Luke 13:11-13)
Spirit of jealousy (Genesis 4:5-8; Numbers 5:14)
Spirit of slumber (Isaiah 29:10, Romans 11:8)
Spirit of the world (I Corinthians 2:12)
Spirit of whoredoms (Hosea 4:12, 5:4)
Unclean spirit (Mark 6:7; Luke 11:24-26)
An evil spirit can be cast out of a person through the name of Jesus and through his Blood . Jesus gives us a wonderful promise in John 14:16-17, 26, "And I will pray the Father, and He will give you another Helper, that He may abide with you forever—the Spirit of truth, whom the world cannot receive, because it neither sees Him nor knows Him; but you know Him, for He dwells with you and will be in you. But the Helper, the Holy Spirit, whom the Father will send in My name, He will teach you all things, and bring to your remembrance all things that I said to you."
The Holy Spirit convicts us of our sin and moves in the life of the believer to equip him or her in the service of God. We repent and take a decision to turn away from our sins and walk towards God. ‘The fruit of the Holy Spirit is love, joy, peace, patience, kindness, goodness, faithfulness, gentleness (meekness), self-control against such things there is no law’ (Galatians 5:22 , 23).
The holy spirit is also known by many names a Comforter , Counselor , Advocate, Convicter of sin, Indweller of believers,Intercessor,Spirit of Truth,spirit of God/Christ/life,teacher,witness etc. Romans 8:9 tells us that if a person does not possess the Holy Spirit, he or she does not belong to Christ: “You, however, are controlled not by the sinful nature but by the Spirit, if the Spirit of God lives in you. And if anyone does not have the Spirit of Christ, he does not belong to Christ.” Ephesians 1:13-14 teaches us that the Holy Spirit is the seal of salvation for all those who believe: “Having believed, you were marked in him with a seal, the promised Holy Spirit, who is a deposit guaranteeing our inheritance until the redemption of those who are God's possession to the praise of his glory.”
When one becomes born of God and surrenders their life over to Jesus Christ, they are sealed with the Holy Spirit and become a child of God. We can conquer the Evil spirit through the precious blood of Jesus Christ and by the power of the Holy Spirit, prayer, fasting, by the whole armor of God and By the Name of Jesus Christ.