Many Christians believe that Christians cannot be possessed by demons. What is the biblical basis for this belief?
This subject is dealt with succintly and pointedly by a commentator, Greg Boyd. I cannot vouch for his work in general, but this piece caught my attention on this particular topic :
I along with most evangelical scholars and pastors do not believe it possible for a Christian to be “possessed” by a demon or by Satan. Christ in principle defeated Satan, and all who are “in Christ” share in this victory (e.g., John 12:31; Col. 2:13–15; 2 Thess. 3:3; Heb. 2:14–15; 1 John 5:18). Colossians 1:13 assures believers that God “has rescued us from the power of darkness and transferred us into the kingdom of his beloved Son.” If we are delivered from Satan’s kingdom, we certainly cannot be possessed by the evil spirits of that kingdom. In 1 Corinthians 10:21, the apostle Paul emphasizes that a person is either in one kingdom or the other: “You cannot drink the cup of the Lord and the cup of demons. You cannot partake of the table of the Lord and the table of demons.”
Finally, 1 John 4:4 tells us that “the one who is in you is greater than the one who is in the world.” Christians have been redeemed from the power of the evil one and are now “possessed” by the Holy Spirit of God. How could they be owned by God and yet at the same time be “possessed” by a demon? Evil cannot dwell in the presence of God. Since we know that a Christian is one in whom the presence of God dwells by the Holy Spirit, we can be assured that no demon would be able to inhabit the body of a believer at the same time. Each believer’s body is a temple of God, and God does not share his temple with demons (1 Cor. 6:19–20). Thus, while acknowledging that believers can be tempted, harassed, and even oppressed at times by demons, I cannot accept that a genuine follower of Christ can be possessed by them.
At the same time, I would affirm that Christians can be oppressed by demons to the point that they need to be delivered from them. It’s significant to note that the Greek word usually translated “demon possessed” in the New Testament (daimonizomai) is actually best translated “demonized”—which simply means to be under the influence of a demon. Thus, there is no connotation of possession or ownership. Demonized Christians are saved and redeemed members of Christ’s body. However, either through evil done to them or through their own choices, a doorway has been opened to the demonic realm.
Here I’d point out passages that indicate the possibility of demonic influence and attack in the lives of individual Christians and the church in general (e.g., 2 Cor. 2:11; Eph. 4:26–27; 6:10–12; 1 Thess. 2:18; 1 Tim. 4: 1; 2 Tim. 2:26; 1 Pet. 5:6–8). Specific biblical examples of the demonization of believers include King Saul (1 Sam. 16:14–23), Ananias and Sapphira (Acts 5:1–3), the Corinthian believer involved in an incestuous relationship (I Cor. 5:1–13), and Judas Iscariot (John 13:27). Perhaps the strongest case is that of the woman in Luke 13:11–16. This woman had been ill for eighteen years with an ailment caused by a demon. Jesus prayed for her, and she was healed. In verse 16, Jesus explains the situation: “And ought not this woman, a daughter of Abraham whom Satan bound for eighteen long years, be set free from this bondage?” By referring to her as a “daughter of Abraham,” Jesus indicates her authentic faith—she is a true believer. And yet she was afflicted with a demon until Jesus prayed for her healing and deliverance.
It’s also worth noting that many theologians throughout church history, including Martin Luther, acknowledged that Christians could be demonized and in need of deliverance prayer.
The biblical basis is very simple. Being truly possessed by a demon (not merely bothered or oppressed ) means that you are no longer in control of your soul because it is possessed by another being.
This means you are truly a slave to sin.
For the vast majority in the reformed view, a Christian cannot be a slave to sin. Yes someone who claims to be a Christian and is believed to be one by others can become a slave to sin but this proves they were never a Christian.
For those who are led by the Spirit of God are the children of God. The Spirit you received does not make you slaves, so that you live in fear again; rather, the Spirit you received brought about your adoption to sonship. And by him we cry, “Abba, Father.”
Judas would be a good example of someone eventually possessed and proving he never believed:
Luke 22:3-4 Then Satan entered Judas, called Iscariot, one of the Twelve. And Judas went to the chief priests and the officers of the temple guard and discussed with them how he might betray Jesus.
It is possible for a demonic to be repossessed if they do not believe in Christ after being freed from their plight as warned by Christ.
One obvious problem with this concept of the Devil being able to defeat an individual in Christ is logically it also means the Devil can theoretically defeat the whole Church as well. This is unthinkable at its very loathsome origin.
These ideas spring from a lack of awareness of the power or God in Christ reconciling the world to himself upon the merits of his own work and plan. That plan includes the absolute security of every stone used to build his holy temple. None can stand against any stone of that church.