What Can Demons Do?

When I was in high school there was a time I asked a friend to pray for me. I don’t remember what the struggle was, but I do remember my friend’s response. He told me with very clear conviction that I should pray silently because Satan can’t know my thoughts. 

Is that true? What can demons do? What exactly is Satan capable of and what should Christians do to guard against demonic attack? These are good questions, all of which Scripture speaks to. 

Satan’s Limitations

Before looking at what Satan is capable of, it’s helpful to understand what he’s not able to do. 

Satan is not omniscient, omnipresent, or omnipotent. 

Demons and Satan do not know the future. This is seen in the gospels, where Satan is clearly confused about how to tempt Jesus. After Peter rebukes Jesus in Mark 8 by telling him he shouldn’t go to the cross, Jesus makes it clear that Peter is being used as an instrument of Satan to tempt him not to go to the cross. Yet, later Satan enters into Judas’ heart (Mark 14:10-11) to tempt him to betray Jesus that he might die. It’s clear that Satan doesn’t know the future, but is trying to thwart Jesus as he understands things. 

Satan and demons do not know all things, including the future. They cannot be all places or know our thoughts and minds. But that doesn’t mean Satan is powerless. 

Satan’s Abilities

Satan and demons are certainly limited in what they can do, but they are still able to do many things.

Geopolitical Influence

Satan is capable of building up empires and giving great authority to evil leaders. Revelation 13:2-3 says, “And the beast that I saw was like a leopard…And to it the dragon gave his power and his throne and great authority.”

There is certainly debate about who or what exactly the beast is. But whether the beast represents a person or an empire, its authority and power is given to it by the dragon who clearly is Satan. In 2 Corinthians 4:4, Paul refers to Satan as the god of this world, and as the god of this world we has power to stir up certain leaders or empires to do his bidding. 

Physical Affliction

Satan is also able to afflict people physically. There is the woman stricken with the spirit of infirmity in Luke 13:11, the man’s son afflicted with a demon which “often cast him into fire and into water to destroy him” (Mark 9:22), and the man in Matthew 9:33 who was mute because of a demon. 

However, Scripture distinguishes between normal sicknesses and demonic activity. In Matthew 4:33 we read, “So his fame spread throughout all Syria, and they brought him all the sick, those afflicted with various diseases and pains, those oppressed by demons, epileptics, and paralytics, and he healed them.” 

By declaring demon oppression a separate category from other sickness, it’s clear that the gospel writers did not simply see all sickness as demonic activity. But it also makes clear that in certain instances demonic power is behind the illness. 

Possession

When people think of demonic influence in the New Testament demon possession perhaps comes to mind. There are numerous occasions where people are seemingly controlled by demons. The most famous of these instances is in Mark 5 where Jesus meets a man with an unclean spirit. This man lived naked among the caves because no one could restrain him. He cried out, it would seem involuntarily, “What have you to do with me Jesus, Son of the Most High God?” When Jesus rebuked the unclean spirit he asked the man, “What is your name?” The man responded, “My name is legion, for we are many.” 

This man, like others, was overpowered by a demon as Jesus said was possible in Matthew 12:43. As stated before, Scripture differentiates between demonic activity and normal sickness, therefore every instance of mental illness or sickness isn’t the result of demon possession or demonic activity, but it is possible. 

However, Scripture is clear that genuine believers in Christ cannot be overpowered by demons. In Romans 6:14, Christians are promised that sin will not have dominion over us. Also, since Christians are indwelt with the Holy Spirit, they cannot be simultaneously indwelt and controlled by demons. That seems to be the point Jesus is making in Matthew 12:43 when he argues that if a house is swept and empty after a demon leaves then the demon will simply return. The conclusion is that we cannot simply be cleaned up and left empty but must be filled with the Holy Spirit. 

But Christians can suffer various kinds of demonic attack. Paul was sent a messenger of Satan to torment him because of his great revelations (2 Cor. 12:7). Though Christians may not suffer demonic possession, they must always be on guard against demonic attack, which leads to the last of Satan’s abilities. 

Power to Influence Our Thoughts

Was my friend right to say that Satan can’t know our thoughts? It’s complicated. We know that Satan does not know all things, including our thoughts or hearts. God alone is omniscient. 

Yet, Scripture is clear that Satan can influence our thoughts and hearts. 

Consider these verses:

2 Cor. 4:4, “In their case the god of this world has blinded the minds of the unbelievers, to keep them from seeing the light of the gospel of the glory of Christ, who is the image of God.”

John 13:2: “During supper the devil had already put it into the heart of Judas Iscariot, Simon’s son, to betray him.”

Acts 5:3, “Ananias, why has Satan filled your heart to lie to the Holy Spirit and to keep back for yourself part of the proceeds of the land?”

1 Chron 21:1, “Then Satan stood against Israel and incited David to number Israel.”

Satan cannot know our thoughts, and he cannot control believers, but it’s clear he can influence our thoughts and actions. Yet, how this happens is quite a mystery. In any case, people are always culpable. It appears that Satan more so works within people’s own sinful desires rather than planting sinful desires in their hearts. John Piper comments on this using Judas as a prime example:

it doesn’t mean for Judas, and it doesn’t mean for us — that the intention and the desire did not arise out of Judas’s own sinful nature. He’s described in John 12:6 as a thief who is taking money out of the disciples’ money bag. It says he’s a person who had no heart for the poor, which means he was also a liar, which also means he was greedy. So we can infer pretty certainly from this that Jesus was not the kind of Messiah Judas wanted to follow. He had other things going on in his mind and heart. All Satan had to do was intensify and direct Judas’s own sinfulness. That’s true with us as well. There’s no clear fine line between the thoughts that Satan puts and the thoughts that we come up with, or the desires that Satan puts and the desires that we come up with.

When Satan beckons us to sin with deceptive thoughts or desires, our own sinful nature kicks in and makes those beckonings more attractive.

Satan and demons can incite us to sin, which is why we must not give him an opportunity (Eph. 4:27). That leads us to our last point. 

What Do We Do?

Walk in the Truth

As Piper points out in the same post as the quote above, we must walk in the truth. Truth is the opposite of what Satan wants and so if we are to resist the Father of Lies, we must be children of the light and hold fast to the truth of God’s Word. When Satan sought to tempt Jesus to sin, Jesus put on a masterclass of how to fight lies with the truth of God’s Word. We must also be equipped with God’s Word so that we don’t twist it or ignore it as Satan tried to get Jesus to do. 

Focus on Fighting Sin

Wayne Grudem points out that there isn’t an emphasis in the New Testament on resisting demonic activity. Rather, the focus is fighting personal sin. Grudem writes, “When the church is guilty of dissension, Paul doesn’t say to rebuke a spirit of dissension but to agree with one another.” We must fight for holiness and resist sin regardless of who put the sinful thought or desire there. 

Rest in Christ

Though we must beware of the dangers we face as Christians from the rulers, authorities, and cosmic powers over this present darkness in the world (Eph. 6:12), we also shouldn’t tremble because we know that greater is he who is in us than he who is in the world (1 John 4:4). Demons do nothing God doesn’t allow them to do (Rev. 20:1-3; Mark 9:23). They tremble in his presence and rightly so because he triumphs over them and humiliates the powers and authorities of this world (Col. 2:15).

Conclusion

C.S. Lewis wrote in The Screwtape Letters, “There are two equal and opposite errors into which our race can fall about the devils. One is to disbelieve in their existence. The other is to believe, and to feel an excessive and unhealthy interest in them. They themselves (the devils) are equally pleased by both errors and hail a materialist or a magician with the same delight.”

Satan and demons are real and have real power to attack us and fan the flame of our own sinful desires. We must be aware of that and take up the armor of God. Yet, we should be more confident in God’s power to save and protect us from all the powers of hell. 

God’s all-powerful protection of us against demonic forces is summed up well in the hymn How Firm a Foundation:

“The soul that on Jesus hath leaned for repose,
I will not, I will not desert to its foes;
that soul, though all hell should endeavor to shake,
I’ll never, no, never, no, never forsake.”


Mike McGregor

Mike McGregor (MDiv, Reformed Theological Seminary) is Director of College Ministry at First Baptist Church in Durham, N.C. You can follow him on Twitter at @m5mcgregor.


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