The task of the Bishop and his hit man is to thwart the unveiling of what Teabing modestly calls “the greatest secret in modern history,” so powerful that, "if revealed, it would devastate the very foundations of Christianity." Later, realizing that this sounds a little meek and mild, he stretches it to "the greatest coverup in human history." As a rule, you should beware of any movie in which characters utter lines of dialogue whose proper place is on the advertising poster. (Just imagine Sigourney Weaver, halfway through "Alien," turning to John Hurt and explaining, "In space, no one can hear you scream.")
Sound advice really. And so, so true.