Demon possession is seen frequently throughout the New Testament. But how does demon possession work? Is it the cause of maladies such as mental illness, meaning that exorcism is the correct treatment? Is demon possession something Christians need to worry about nowadays?

Demon Possession Then

First, let’s clear up what was happening during the Last Days, and then we can turn to the current situation. Something that struck me as odd once I noticed it is that in Jesus’ day, there were lots of faithful Jews who loved and worshipped God but who were suffering demonic affliction. We know this because Jesus healed via exorcism lots of people who came to Him in faith. But how was their suffering possible in the first place?

Well (H/T James B. Jordan), after the Exile, God made new rules for priests. In Ezekiel 44:10-16, He specified that only descendants of Zadok the priest would be allowed to serve as priest or High Priest anymore. All other Levites, even other sons of Aaron, would only be allowed to perform support duties for the Zadokite priests.

However, when Antiochus Epiphanes removed Jason (a Zadokite) as High Priest and replaced him with Menelaus (not a Zadokite), God’s requirement was violated. Of course, the Maccabees eventually restored proper temple worship after they recaptured Jerusalem from Antiochus’ forces, but they afterward established themselves as High Priests. Even though they were priestly, they were not Zadokites, which meant this action was sinful and the office of High Priest was now illegitimate.

This was highly significant, because only the High Priest could perform the ceremony known as the “Day of Atonement,” during which all the elements of the sacrificial system were cleansed and all leftover sins that hadn’t been addressed through a specific sacrifice were wiped out each year (Leviticus 16). Because of the illegitimacy of the High Priest, by the time Jesus came around, Judah had been teeming with unaddressed sin, and the worship system itself was spiritually dirty.

This spiritual filthiness that built and built over time gave demons purchase over the faithful of Israel. That is why so many believers were suffering a variety of illness and maladies. However, because Jesus was the High Priest of the New Covenant (Hebrews 2:17), He had the authority to apply the power of the imminent substitutionary atonement of His death upon the cross to believers and bring them under the purview of the kingdom of heaven. Thus, He could heal people by removing the spiritual purchase demons had in their lives, driving them out and eliminating the illnesses.

Demon Possession Now

Nowadays, the faithful are under the power of the New Covenant that is better than the Old Covenant (Hebrews 7:22), which means the spiritual system put in place by Jesus will forever be clean and holy, and His atonement will forever be effective. Therefore, we Christians are generally protected from the power of demons. However, if we yield to sin, we can open portals to demons in our lives, as Judas did to Satan (John 13:27). We must then repent and realign ourselves with God’s will to drive demons out of our lives.

As far as illnesses go, the world is in the bondage of corruption (Romans 8:21). This means creation is broken, and bad things like natural disasters and medical problems now occur. Our susceptibility to them is based on two factors: our individual relationship with God and the relationship with God of the collectives we belong to. For example, if we live in a wicked nation, we can suffer the way that others in our nation suffer, because we lack the protective covering that God puts over a faithful nation (Deuteronomy 7:12-15). 

This is hard for us as Americans to accept, because we are very individualistic and don’t like the idea that the course of our lives can be determined by factors outside of our control. Still, there are positive aspects to this: for example, there are many wicked people in America who have plentiful access to food and medical care because of the ways our forefathers served God and tried to set up society in a way that was pleasing to Him. Thus, you can experience blessing because of the faithfulness of others, regardless of your own behavior.

Therefore, people nowadays can suffer because of their own wickedness or because of the wickedness of some collective they belong to (nation, state, city, church, company, etc.), weakening or forfeiting God’s protection from the hostility of creation and experiencing illnesses as a result. The extent to which these sufferings represent “demonic affliction” or just the brokenness of nature is debatable. I will simply point out that demonic possession was responsible in the New Testament for illnesses that we regularly treat today with medicine, such as epilepsy (Matthew 17:14-18).

Therefore, despite a popular misunderstanding amongst Christians, mental illness is not special amongst demonic afflictions, and just because exorcism was used to treat it in Mark 5:1-20 doesn’t mean it should still be used today, any more than we use exorcism for epilepsy. In truth, the brain is an organ. It can have medical issues just like the heart or liver or pancreas. We should treat it medically just like we do any other organ.

The brain only gets treated differently because, unlike any other organ, its maladies can affect our personality, which is intimately tied to our identity and therefore comes across as more alarming than a typical physical ailment. When that factor is combined with the stigma and ignorance surrounding mental illness, we get this confusion. Psychiatry and related medical disciplines are currently the best approach we have for treating mental illnesses, even for Christians.