Why do authority or priests are necessary to perform an exorcism?
Priests perform exorcisms on the Church’s authority, not on their own. The Church is given its authority by Christ, so the effectiveness of the exorcist is not directly contingent on the personal strengths of the priest. Nonetheless, an exorcism is pretty heavy stuff, and for the priest’s own sake the Church requires that he be “properly distinguished for his piety, prudence, and integrity of life. He should fulfill this devout undertaking in all constancy and humility, being utterly immune to any striving for human aggrandizement, and relying, not on his own, but on the divine power. Moreover, he ought to be of mature years, and revered not alone for his office but for his moral qualities.” If a normal Joe tried to perform an exorcism, he would be trying to do it on his own authority, without the help of the Church, so he’s not likely to succeed and could very well end up in deep spiritual trouble himself.
