I was asked to help someone by describing how deliverances from demons come about. At first, I thought to do justice to the subject, one needs to write a book, but on reflection I think a few key thoughts work fine. Here then are those key thoughts:
I have been a witness to many of deliverances…and they were not all done the same way. In the Biblical record, we see that they were done various ways, so it is probably wise not to get into the mind-set that there is only one technique.
What do demons dislike and what takes authority over them? A very righteous person full of the Holy Spirit drives them away…they don’t like to be close to the power of the Spirit. Wherever Christ went, the demons wanted to naturally flee. They don’t like the blood of Jesus Christ, applying the righteous blood of Jesus Christ all over an area will drive them out. For instance, flood the mind and all its hidden places with the blood. However, it may not even take this much. Believers in good standing with their heavenly Father have authority over demons and can simply command them to leave. I have seen this work quite well. The believer simply uses his authority over them. They are granted permission to enter a believer; the believer has in some way thru his will allowed them to enter. The believer may not have explicitly said, I want such & such demon to come into me, but when their mind submits to certain temptations, the portals are opened for those demons to come in, and they take advantage of it immediately. Once they make a home, they know that if they are ever cast out, they can wait & generally will be soon invited back in.
There are more powerful demons that can take stronger actions to cast out. Certain sicknesses are helped demonically via rights/portals related to certain sins. By confessing & repenting of those sins first, then the demons are denied access, and the effect they are having on the body is stopped, & the body can heal itself of that particular ailment which was largely demonic-based. Not all ailments are demonically created, so in some cases this approach does not help medically. In these other situations, the demonic may be coming in via the food portals/rights. The person by eating junk and dishonoring their temple has created physical weaknesses. In these cases, the person needs to repent and eat the God/temple honoring food. Repenting of eating junk will help take away the right of these demons to remain. Demons can be driven out easily, we just need to delete whatever we did to allow them to enter. Taking oaths, vows and occult covenants is one way people give demons jurisdiction. Renouncing those vows & oaths will take away the legal right of demons to stay. Then we can cast them out more easily. Some demons are so strong that we need to purify our bodies with fasting before we can get them out.
And this last point is a natural lead-in to where I think people miss the main point. The main point is that common demons live in hierarchies, take orders, and are granted permission or the authority to enter a person. That is the issue, the authority that allows them to infest a person. Sometimes that authority is given obliquely. If you get close to a demonically infested person, like getting fleas, you can have some of their demons jump on you. Going into dark geographic areas may give permission for demons to jump onto you. In both cases, there was likely an underlying spiritual weakness (a weak spiritual immune system) that allowed access. A strong believer full of the Spirit & walking in faith would likely have naturally repelled them. I have witnessed strong believers go anywhere, say into a Hindu temple, or onto campuses controlled by witches and walk out free of infestation. Stronger is He that is in you, than those of the other side. But note that things like fear will draw them in. Generational sins & curses have to be broken. Curses & sins from our culture can make us vulnerable also. When we determine how the demon got authority to come into our life, and we break that authority and order it to go it will simply leave. Some have such powerful control over a person that the controlled person may shake and pass out when the demon leaves. Some persons who want to cast out demons get all worried that it has to be ritually done right and said under a certain name, “In the name of Jesus Christ of Nazareth”, or “In the name of Yahoshua”, etc. Certainly, the demon(s) need to know what authority is directing them to leave, but I have seen deliverances take place without any name of God or form of Christ’s name used, simply because the demon’s job and authority was cancelled. So deliverance is an authority issue, not an issue of performing some ritual correctly.
My goal with this has been to keep it short & simple. Many books have been written on the details, some with merit, and of course others off track. As we are advised, Seek ye first the kingdom of God and His righteousness, and all these things will be added. There is no substitute for the power that comes from spiritual purification, which naturally brings in the Holy Spirit. Indwelling us in power, the Holy Spirit becomes a force field of natural protection. Pray for spiritual discernment of what one needs to do to get completely right with God. These things are specifics related to your life. For instance, Samson by allowing his hair cut created a weakness. Perhaps there is someone you need to ask to forgive you. Make right what you have done wrong, and regain spiritual strength.