What is an overview of beliefs on how one can become demon-possessed?

What is an overview of beliefs on how one can become demon-possessed?

It seems to me that thee number one cause for becoming diabolically possessed is leading a very grievously sinful life.

For myself, a sure help is to try and completely avoid the Devil as best as possible in all things. He is one bad dude.

Be sober and watch: because your adversary the devil, as a roaring lion, goeth about seeking whom he may devour. - 1 PETER 5:8

Or as St. Augustine puts it:

He (the devil) is tied up like a dog on a chain, and can only bite someone who, deathly sure of himself, goes near him. Wouldn’t you think a man a fool who let hiimself be bitten by a chained up dog?

He can only bite those who willingly let him. It is not by force, but by persuasion, that he harms: he asks for our consent, he does not drag it from us.

Fr. Gabriele Amorth in his book, An Exorcist Tells His Story (pages 56-63) gives the following reasons for persons becoming possessed by the devil:

1. With God's permission.

2. Being cursed by someone.

3. When subject to an evil eye.

4. A grave and hardened state of sin.

5. Association with evil people and places.

I know this does not seem fair, but a saint or someone living a saintly life could be diabolically possessed and there are examples to prove this.

St. Benedict of Nursia dealt with the enemy of mankind on several occasions as we can see in the Dialogues of St. Gregory. In Chapter 30, for example St Benedict delivered a monk from the hands of the Evil One, who wanted to disrupt the building of a monastery.

Ouija Boards is another example that Christians should not play with and considered a no-no. Mainstream Christian denominations, including Catholicism, have "warned against using Ouija boards", holding that they can lead to demonic possession.

Exorcism of Roland Doe is just one example of an exorcism due to using a Ouija Board.

Since early in the Ouija board's history, it has been criticized by several Christian denominations. The Catholic Church in the Catechism of the Catholic Church in paragraph 2116 explicitly forbids any practice of divination which includes the usage of Ouija boards. Also, Catholic Answers, a Roman Catholic Christian apologetics organization, states that "The Ouija board is far from harmless, as it is a form of divination (seeking information from supernatural sources)." Moreover, Catholic bishops in Micronesia called for the boards to be banned and warned congregations that they were talking to demons when using Ouija boards. In a pastoral letter, The Dutch Reformed Churches encouraged its communicants to avoid Ouija boards, as it is a practice "related to the occult". The Wisconsin Evangelical Lutheran Synod also forbids its faithful from using Ouija boards as it teaches that such would be a violation of the Ten Commandments.

In 2001, Ouija boards were burned in Alamogordo, New Mexico, by fundamentalist groups alongside Harry Potter books as "symbols of witchcraft". Religious criticism has also expressed beliefs that the Ouija board reveals information which should only be in God's hands, and thus it is a tool of Satan. A spokesperson for Human Life International described the boards as a portal to talk to spirits and called for Hasbro to be prohibited from marketing them.

These religious objections to use of the Ouija board have in turn given rise to ostension type folklore in the communities where they circulate. Cautionary tales that the board opens a door to evil spirits turn the game into the subject of a supernatural dare, especially for young people. Ouija Boards

Lutheranism holds the possibility of possession can afflict anyone.

However, Lutheranism seems to draw a distinction between bodily possession (possible for believers) and spiritual possession of the soul of believers (impossible).

The Lutheran Church traces the practice of exorcism to the Scriptural claim that Jesus Christ expelled demons with a simple command (Mark 1:23–26; 9:14–29; Luke 11:14–26). The apostles continued the practice with the power and in the name of Jesus (Matthew 10:1; Acts 19:11–16). Contrary to some denominations of Christianity, Lutheranism affirms that the individual, both the believer and the non-believer, can be plagued by demons, based on several arguments, including the one that "just as a believer, whom Jesus Christ has delivered from sin (Romans 6:18), can still be bound by sin in his life, so he can still be bound by a demon in his life." - Exorcism in Christianity

In the Pentecostal Churches tend to believe that a "spirit-filled Christian" cannot be possessed, based on their beliefs.

Reason for the possibility: Grievous sin against God are always possible post conversion and baptism of all believers whether Catholic, Orthodox, Lutheran Anglican or Protestant. All must work with Divine Graces accorded to every individual believer regardless of denomination.

In the Pentecostal Church, Charismatic Movement, and other the less formalized sections of Christianity, the exorcism ritual can take many forms and belief structures. The most common of these is the deliverance ceremony. Deliverance differs from the exorcism ceremony in that the Devil may have gotten a foothold into a person's life rather than gaining complete control . If complete control has been gained, a full-fledged exorcism is necessary. However, a "spirit-filled Christian" cannot be possessed, based on their beliefs. Within this belief structure, the reasons for the devil to get a foothold are usually explained to be some sort of deviation from theological doctrine or because of pre-conversion activities (like dealing with the occult). - Exorcism in Christianity

Certainly one invites possession when one initiates contact with demons. This could be through physical objects such as ouija boards, which are thought to have supernatural powers (a form of idolatry in violation of the second commandment), or through direct appeal (in violation of the first commandment).

Using a medium, King Saul tried to make contact with spirits other than God:

Then Saul said to his servants, “Find me a woman who is a medium, that I may go to her and inquire of her.” And his servants said to him, “In fact, there is a woman who is a medium at En Dor.” … And he said, “Please conduct a seance for me, and bring up for me the one I shall name to you.” … And the king said to her, “Do not be afraid. What did you see?” And the woman said to Saul, “I saw a spirit ascending out of the earth.”
— 1 Samuel 28:7–13

We know this spirit couldn't have actually been Samuel, who was buried and unconsciously awaiting resurrection (e.g. Ecclesiastes 9:5 "the dead know nothing"). Whether a demon possessed Saul at this point, or whether he was already possessed, we don't know, but he went downhill after this, eventually killing himself.

In Acts 16:16, we are told of a "slave girl possessed with a spirit of divination … who brought her masters much profit by fortune-telling", again illustrating the link between the spirit world and possession.

But when it comes to inviting Satan into our lives, such deliberate contact isn't required. There is a far more common cause.

Paul describes how Satan can make use of us, when our hatreds, resentments, etc. leave us open to his influence:

… on the contrary, you ought rather to forgive and comfort him, lest perhaps such a one be swallowed up with too much sorrow. Therefore I urge you to reaffirm your love to him. For to this end I also wrote, that I might put you to the test, whether you are obedient in all things. Now whom you forgive anything, I also forgive. For if indeed I have forgiven anything, I have forgiven that one for your sakes in the presence of Christ, lest Satan should take advantage of us; for we are not ignorant of his devices.
— 2 Corinthians 2:7–11

Again, Paul warns about the importance of forgiveness, and how failure to forgive creates a place for the devil:

Therefore, putting away lying, “Let each one of you speak truth with his neighbor,” for we are members of one another. “Be angry, and do not sin”: do not let the sun go down on your wrath, nor give place to the devil. … Let all bitterness, wrath, anger, clamor, and evil speaking be put away from you, with all malice. And be kind to one another, tenderhearted, forgiving one another, even as God in Christ forgave you.
— Ephesians 4:25–32

Forgiveness is perhaps the single-most important aspect of Christianity. It is how God shows love, and it is how Christians show their love.

Jesus presented a model prayer, which praises God and asks for certain things. But it contains only one promise that the person praying offers: "forgive us our debts, as we forgive our debtors".

Jesus then goes on to emphasize the importance of forgiveness:

For if you forgive men their trespasses, your heavenly Father will also forgive you. But if you do not forgive men their trespasses, neither will your Father forgive your trespasses.
— Mark 6:14–15

Failing to forgive puts a terrible burden on one's mind, and that creates an open invitation for possession.

Even the secular world, which denies demon spirits, recognizes that long-time hatreds and grudges can seriously affect mental well-being, and literally refers to such afflictions as demons.

Whether one is a Christian or not, forgiving and ridding oneself of festering negative thoughts is perhaps the best thing one can do for oneself.