Steve Martin has one of his best roles in Leap Of Faith as Jonas Nightengale, a high-tech faith healer and revival preacher who takes pride in the money he squeezes out of people, convincing himself that he can't deliver hope, but "I give my people a good show." As the film begins, Nightengale's truck caravan breaks down and his troupe finds itself stranded in the backwater town of Rustwater, Kansas. Nightengale figures that as long as he's there, he might as well set up the rubes and put on a performance. With the aid of his assistant Jane (Debra Winger) (who talks to Nightengale through an earpiece, informing him of the physical problems of certain members of his audience), Nightengale puts on a glorious show and rakes in the money. But the local sheriff Will (Liam Neeson) wants to shut down the show because times are bad in Rustwater and he doesn't think folks should waste their money on a charlatan. Nightengale sends Jane to seduce Will, but the sheriff succeeds in getting Jane to fall in love with him. Nightengale also meets someone, Marva (Lolita Davidovich), a local waitress with a crippled brother. The boy thinks Nightengale can heal him. Nightengale tries to make the child understand that he can't help him, but it turns out that Nightengale knows very little about his own faith powers.
~ Paul Brenner, All Movie Guide