How do I respond to a demon-possessed person?

Scripture tells us that the struggles we have in serving Christ and reaching the world with the Gospel always have a spiritual origin:

Eph. 6:11 Put on the full armor of God, so that you will be able to stand firm against the schemes of the devil. 
Eph. 6:12 For our struggle is not against flesh and blood, but against the rulers, against the powers, against the world forces of this darkness, against the spiritual forces of wickedness in the heavenly places.

The enemy and his demons may inhabit the body of any unbeliever as the Lord permits, and by that indwelling may manipulate and control them causing them to do many violent and extreme things (usually attributed to mental illness by the unbelieving world). Even among those unbelievers who aren’t possessed directly, the enemy still maintains a degree of control through the fear of death. These are the ones Jesus came to free by faith:

Heb. 2:14  Therefore, since the children share in flesh and blood, He Himself likewise also partook of the same, that through death He might render powerless him who had the power of death, that is, the devil, 
Heb. 2:15 and might free those who through fear of death were subject to slavery all their lives. 

By your testimony, we assume you have encountered demon-possessed individuals, and this is not uncommon. We believe there are many demon-possessed people around us in the world, though unbelievers and even many believers are unwilling to acknowledge this reality. We commend you for having the spiritual wisdom to recognize the situation accurately and to seek counsel on how best to respond.  

First, a believer has no reason to fear the enemy, since the Holy Spirit in us has far greater power than does the enemy:

1John 4:4 You are from God, little children, and have overcome them; because greater is He who is in you than he who is in the world. 

Our eternal fate is secure in Christ, so the enemy can do nothing greater than taking our earthly life, and scripture says that since our body will die one way or another, this is nothing important. Rather, we only live in fear of the Lord:

Matt. 10:28 “Do not fear those who kill the body but are unable to kill the soul; but rather fear Him who is able to destroy both soul and body in hell.

Furthermore, a believer cannot be indwelled by a demon, since the Holy Spirit's presence within the believer will not permit the enemy access. As Jesus taught by way of a parable:

Matt. 12:43  “Now when the unclean spirit goes out of a man, it passes through waterless places seeking rest, and does not find it.
Matt. 12:44 “Then it says, ‘I will return to my house from which I came’; and when it comes, it finds it unoccupied, swept, and put in order.
Matt. 12:45 “Then it goes and takes along with it seven other spirits more wicked than itself, and they go in and live there; and the last state of that man becomes worse than the first. That is the way it will also be with this evil generation.”

In the parable, the evil spirits returned to the “empty” house (i.e., unbeliever's body) because nothing prevented them from returning, but if the house has been claimed during their absence (i.e., by the Holy Spirit as a result of faith in the Messiah), then the evil spirits would not have been able to reside again. Jesus was teaching this parable to make a point about the unbelief He encountered in Israel. Nevertheless, His message is equally relevant for us today. Once we are "occupied" by the Holy Spirit, the Lord hangs a "No Vacancy" sign outside our body denying demons entry. 

Despite possessing the Holy Spirit, believers possess no special power over the enemy. Scripture tells us to understand that the enemy and his demons have real power and not to think ourselves greater than they:

Jude 9 But Michael the archangel, when he disputed with the devil and argued about the body of Moses, did not dare pronounce against him a railing judgment, but said, “The Lord rebuke you!” 

2Pet. 2:10 and especially those who indulge the flesh in its corrupt desires and despise authority.  Daring, self-willed, they do not tremble when they revile angelic majesties, 
2Pet. 2:11 whereas angels who are greater in might and power do not bring a reviling judgment against them before the Lord. 

The Bible teaches that we do not possess power over the devil, since God made angels more powerful than human beings. In fact, Peter teaches that the devil outranks even the most powerful angel, so certainly we should not expect to have power over him! Obviously, the Lord may permit us to prevail over the enemy in a given situation, but even then it is the Lord's power that overcomes the enemy, not our own. Conversely, when the enemy gains some measure of success against us (see the book of Job), we know the Lord has permitted this outcome for the purpose of strengthening us spiritually in the hope we might receive a blessing:

1Pet. 5:8 Be of sober spirit, be on the alert. Your adversary, the devil, prowls around like a roaring lion, seeking someone to devour. 
1Pet. 5:9 But resist him, firm in your faith, knowing that the same experiences of suffering are being accomplished by your brethren who are in the world. 
1Pet. 5:10 After you have suffered for a little while, the God of all grace, who called you to His eternal glory in Christ, will Himself perfect, confirm, strengthen and establish you.  

Therefore, the scripture never directs a believer to confront the enemy or his demons. Any such action is presumptuous on our part, since it assumes the Lord will always act on our behalf to give us victory against the enemy's schemes (which is not necessarily true...see Job again!). Unless the Lord has specifically directed us to confront the enemy's agents in some way, we should not venture to challenge the demonic realm. On the contrary, we respect their power, resist their attempts to tempt us into sin, and rest in the Lord's protection by His Spirit. 

In fact, scripture promises that if we resist the enemy's efforts to lead us astray, he will eventually flee:

James 4:7 Submit therefore to God. Resist the devil and he will flee from you. 

In light of the earlier scripture, we know that resisting the enemy doesn’t mean actively fighting him but rather it means not giving into his temptations. 

In summary, we should not fear the enemy but neither should we imagine we have power against him. When we see someone possessed by the demonic realm, we should understand that the person is not our enemy, since our enemy is not flesh and blood. Nevertheless, we should not attempt to fight the power of the demon inside the person by our power. Should the Spirit direct us in some way against the person, then we should obey and operate in the Spirit. Otherwise, we should act wisely by resisting any temptation of the enemy to respond in anger, hatred or pride.

For more information on this topic, we recommend you take our Jude study.

Scripture quotations taken from the (NASB®) New American Standard Bible®, Copyright © 1995, 2020 by The Lockman Foundation. Used by permission. All rights reserved. www.lockman.org