Compared to this searing version of Sinclair Lewis' novel, movies like Leap Of Faith have been soft on hypocritical evangelists.
Lancaster won an Oscar as the eponymous fire-breathing bible-basher, a heaven huckster who preaches a blue streak and then indulges in as many sins of the flesh as could be shown in a 1960 film. Elmer latches onto sincerely saintly Jean Simmons and corrupts her crusade (and, of course, her) by invoking the Almighty as he chases the almighty dollar and preaching that the lion shall lay down with the lamb as he sets about laying down with anything in a skirt.
Bitingly satirical at first, with Lancaster prefiguring Steve Martin by making the awful Elmer almost bearable because he's so entertaining, this gets progressively nastier and winds up with an impressive hellfire finish.