Elmer Gantry (1960) on Netflix

Elmer Gantry is a fast-talking, hard-drinking traveling salesman who always has a risqué story and a hip flask to entertain cronies and customers alike. He is immediately taken with Sister Sharon Falconer, a lay preacher whose hellfire-and-damnation revivalism has attracted quite a following. Gantry uses his own quick wit and Bible knowledge to become an indispensable part of Sister Sharon's roadshow, but his past soon catches up with him in the form of Lulu Bains, now a prostitute. While Gantry seeks and eventually gets forgiveness from Sharon, tragedy strikes when she finally manages to get out of her revivalist tent and opens a permanent church.