As promised in my preaching, here are some additional resources on spiritual warfare that might help:
CS Lewis warns us not to underestimate the devil. Some Christians go the opposite route and really fear him to death. To strike a balance is to be biblical about it.
In my preaching I mentioned about sin opening the door for the enemy to operate. My last post was on the ordinary demonic. The contention was that anything sinful is evil of nature thus demonic but there are some sins that would result in extra ordinary demonic activities and manifestations in their lives.
Extraordinary Demonic
• Torment (Acts 5:16)
Acts 5:16 Also a multitude gathered from the surrounding cities to Jerusalem, bringing sick people and those who were tormented by unclean spirits, and they were all healed.
• Physical injury (Matt. 9:32–33; 12:22–23; Acts 8:4–8)
Matt. 9:32 ¶ As they went out, behold, they brought to Him a man, mute and demon-possessed.
Matt. 9:33 And when the demon was cast out, the mute spoke. And the multitudes marveled, saying, “It was never seen like this in Israel!”
• False miracles (Acts 8:9–23; 16:16; 2 Thess. 2:9–10)
Acts 16:16 ¶ Now it happened, as we went to prayer, that a certain slave girl possessed with a spirit of divination met us, who brought her masters much profit by fortune-telling.
• Accusation (Rev. 12:10)
Rev. 12:10 ¶ Then I heard a loud voice saying in heaven, “Now salvation, and strength, and the kingdom of our God, and the power of His Christ have come, for the accuser of our brethren, who accused them before our God day and night, has been cast down.
o Vain regrets and condemnation (Rom. 8:1)
Rom. 8:1 There is therefore now no condemnation to those who are in Christ Jesus, who do not walk according to the flesh, but according to the Spirit.
– Death (Prov. 8:36)
Prov. 8:36 But he who sins against me wrongs his own soul; All those who hate me love death.”
– Murder/Suicide (John 8:44)
John 8:44 You are of your father the devil, and the desires of your father you want to do. He was a murderer from the beginning, and does not stand in the truth, because there is no truth in him. When he speaks a lie, he speaks from his own resources, for he is a liar and the father of it.
– False spirits (1 John 4:1–6)
1John 4:1 Beloved, do not believe every spirit, but test the spirits, whether they are of God; because many false prophets have gone out into the world.
1John 4:2 By this you know the Spirit of God: Every spirit that confesses that Jesus Christ has come in the flesh is of God,
1John 4:3 and every spirit that does not confess that Jesus Christ has come in the flesh is not of God. And this is the spirit of the Antichrist, which you have heard was coming, and is now already in the world.
1John 4:4 ¶ You are of God, little children, and have overcome them, because He who is in you is greater than he who is in the world.
1John 4:5 They are of the world. Therefore they speak as of the world, and the world hears them.
1John 4:6 We are of God. He who knows God hears us; he who is not of God does not hear us. By this we know the spirit of truth and the spirit of error.