Exorcism, meaning "binding by oath", is the religious or spiritual practice of purportedly evicting demons or other spiritual entities from a person or an area they are believed to have possessed.
Depending on the spiritual beliefs of the exorcist, this may be done by causing the entity to swear an oath, performing an elaborate ritual, or simply by commanding it to depart in the name of a higher power. The practice is ancient and part of the belief system of many cultures and religions.
In Christianity, exorcism is the practice of casting out demons. In Christian practice the person performing the exorcism, known as an exorcist, is often a member of the Christian Church, or an individual thought to be graced with special powers or skills. The exorcist may use prayers and religious material, such as set formulas, gestures, symbols, icons, amulets, etc.
The exorcist often invokes God, Jesus and/or several different angels and archangels to intervene with the exorcism. A survey of Christian exorcists found that most exorcists believe that any mature Christian can perform an exorcism, not just members of clergy. Christian exorcists most commonly believe the authority given to them by the Father, Son, and Holy Spirit (the Trinity) is the source of their ability to cast out demons.
In general, people considered to be possessed are not regarded as evil in themselves, nor wholly responsible for their actions, because possession is considered to be unwilling manipulation by a demon resulting in harm to self or others. Therefore, practitioners regard exorcism as more of a cure than a punishment. The mainstream rituals usually take this into account, making sure that there is no violence to the possessed, only that they be tied down if there is potential for violence.