There are various forms of satanic influence that are often brought to bear by the Devil and his minions upon persons, places, and things. And even though they are sometimes called by different names, or common names applied to differing circumstances or situations, in the end they are limited in scope. The following terms and definitions are to our minds, in general agreement among most experts and authorities. We therefore offer them as common denominators of discussion and for general labeling purposes, especially in diagnoses.
Temptation is the most ordinary and widespread form of Satan's influence upon humankind. But do not be deceived by its commonality, for it is also one of the most powerful weapons in the Devil's arsenal. Humans swim in a sea of temptation where dry land is scarce and being pulled under is a constant threat. Temptations to follow the Devil are many; they are usually extremely enticing and typically draw us to them in the most seemingly innocent or beguiling of manners. Temptations are the steppingstones to sin.
External pain is actual physical pain imposed upon God's loyal subjects. Yet even though it causes great distress, it can harm only the body, not the soul. The greatest danger one faces under the pain of demonic sources is a weakening of one's will against sin. For this reason, the enriching and fortifying effects of prayer, rather than exorcism, is the most powerful defense one can put forward against external pain.
Demonic possession is when a demon takes control of a person's body and mind. The soul remains free and the person remains innocent of thought and deed — morally blameless — as the person is under the full control of demonic forces. Commonly accepted signs of demonic possession include speaking recognizable foreign languages that the person has no knowledge of, knowledge of hidden things, superhuman strength, and intense adverse reactions to religious words and objects. Bear in mind however, that it is very important for the exorcist to use great caution when diagnosing a suspected case of demonic possession. Demonic possession can take many forms, but what one believes are signs can often be indicators of other conditions, even deceit.
Diabolical oppression is no less time-consuming nor difficult to diagnose and heal than demonic possession. Oppression often affects a person's health, but it can just as easily take its toll on relationships, jobs, finances, or other areas of a person's life. Unlike possession however, a person oppressed does not lose control of his or her body or mind, but rather suffers from the adverse effects of the oppression.
Obsession is one of the most difficult forms of demonic influence to accurately diagnose and heal. In essence it is a condition of obsessive thoughts that are irrational, depressive, unrelenting, and destructive both to others and one's self. Obsession usually presents similar to mental illness, sometimes coming in sudden outbursts, sometimes manifesting itself over long drawn-out periods. Obsession almost always invades a person's dreams, leaving the person exhausted, irritable, restless, and fitful — miserable without knowing why — due to forgotten dreams. Obsession is a form of demonic influence best approached by an experienced exorcist with the input and guidance of a licensed mental health professional.
Demonic infestation primarily affects locations, objects, and animals. However, there have been cases of demonic infestations in humans, the most famous being the story of the man from Gerasens as told in Luke 8: 26-40. Infestation denotes an overrunning or spreading of parasites or invaders and the presence of a multitude rather than just a few. This should be borne in mind when an infestation is encountered and dealt with accordingly, but one should also keep in mind that the strength of many as opposed to one is negligible as they remain subject to the authority of Christ.
Satanic subjugation is being enslaved, forced into submission or subservience to the Devil through an act of one's own free will. Subjugation usually occurs when a person makes a pact with the Devil or one of his demons. Often these pacts are made when a human desires something that he or she believes can and will be supplied by the Devil or a demon in exchange for some act or promise from the human. Subjugation requires greater intervention than just an exorcism. Subjugation requires identifying and getting to the root of the person's weakness and building their spiritual strength while simultaneously purging the satanic involvement and influence. This should only be approached by an experienced exorcist with a team.