Analyze the following passage for audience, purpose, tone, and perspective to show the main idea.
"we have been advised by some credible christians yet alive, that a malefactor, accused of witchcraft as well as murder, and executed in this place more than forty years ago, did then give notice of an horrible plot against the country by witchcraft, and a foundation of witchcraft then laid , which if it were not seasonably discovered, would probably blow up, and pull down all the churches in the country. and we have now with horror seen the discovery of such a witchcraft! an army of devils is horribly broke in upon the place which is the center, and after a sort, the first-born of our english settlements: and the houses of the good people there are filled with the doleful shrieks of their children and servants, tormented by invisible hands, with tortures altogether preternatural." (cotton mather, "the wonders of the invisible world")