This is really a classic movie and a major influence on my loss of respect for all religion.

When Marjoe was three, his father, a third generation minister, noticed his son's talent for mimicry and overall fearlessness of strangers and public settings. His parents claimed Marjoe had received a vision from God during a bath and began training him to deliver sermons, complete with dramatic gestures and emphatic lunges.
        By the time Marjoe was four, his parents arranged for him to perform a marriage ceremony for a film crew from Paramount studios, referring to him as "the youngest ordained minister in history." Like much in Marjoe's early life it is hard to say for sure who exactly ordained him, if his father ordained him, or if he was even ordained at all.

      In the late 1960s , Marjoe (mid twenties) suffered a crisis of conscience — in particular about the threats of damnation he felt compelled to weave into his sermons — and resolved to make one final tour, this time on film. Under the pretense of making a documentary detailing a viable ministry, Marjoe assembled a documentary film crew to follow him around revival meetings in California, Texas, and Michigan during 1971. 
        Unbeknownst to everyone else involved — including, at one point, his father — Marjoe gave "backstage" interviews to the filmmakers in between sermons and revivals, explaining intimate details of how he and other ministers operated. After sermons, the filmmakers were invited back to Marjoe's hotel room to tape him counting the money he collected during the day. The resulting film, Marjoe, won the 1972 Academy Award for best documentary. Source: Wikipedia