Midway through Robert Duvall's acclaimed new film, "The Apostle," the Pentecostal minister whom he portrays takes a secretary out on a dinner date. When their food arrives and the woman lifts her fork, Duvall stills her hand. Then he thanks God. And as he does, the woman tightens her face and rolls her eyes, emitting a muffled "Amen."

Her discomfort with a fundamentalist Christian's overt expression of faith might well stand for that of Duvall's usual colleagues and audiences. With the character of Sonny Dewey in "The Apostle," a committed pastor who must rebuild his life and ministry after an act of violence shatters both, Duvall has dared cosmopolitans to accept a preacher who defies Hollywood's standard depiction of soul-saver as flimflammer, whether embodied by Burt Lancaster's Elmer Gantry or Flip Wilson's Reverend Leroy.The evidence from the recent showing of "The Apostle" at the New York Film Festival suggests that Duvall has made converts, at least of the esthetic sort. Janet Maslin of The New York Times called "The Apostle" "a film that can create a full, fiery, warts-and-all portrait of Sonny without reducing him to any kind of stereotype." Equally important to Duvall, one of the ministers who influenced him, the Rev. Johnny Ray Youngblood of St. Paul Community Baptist Church in Brooklyn, flew back from a business trip to Chicago to view the film.

"I wanted to give it credence," Duvall, 66, said of evangelical Christianity in a recent interview in a Manhattan hotel. "To give it full emphasis. We make great gangster movies. So why not make this kind of movie right, too? Church can be so pure unto itself. And it's so contaminated when it's done by TV or Hollywood."

More specifically, the empathy that the entertainment industry has periodically shown for urban, progressive clergymen like Courtney B. Vance's minister in the film "Preacher's Wife" has never extended to the politically and theologically conservative pastors who are liberal Hollywood's enemies in the culture wars.

Faced with reluctance, if not outright resistance, Duvall spent 13 years and $5 million of his own money to make "The Apostle."

Even as Miramax was bidding for the distribution rights to the movie - which went to October Films, which will release "The Apostle" in early 1998 - one of the company's executives confided to Duvall about evangelicals like Sonny Dewey, "I'm terrified of those people."

Duvall's sense of respect for fundamentalism runs decades deeper than the temporal need to promote a film he wrote, directed and starred in. The son of a Methodist father and a Christian Scientist mother, he attended church regularly during his childhood in Annapolis, Md., and has never considered himself anything but a believer.

One might date the genesis of "The Apostle" more precisely, though, to 1962, the year Duvall was rehearsing for the role of a small-town Southerner in an off-Broadway play, "The Days and Nights of Beebee Fenstermaker." As part of the meticulous preparation for which he has since been renowned, he traveled to the character's hometown of Hughes, Ark.

Spending the night in that sleepy Delta crossroads, Duvall discovered little diversion except for a tiny Pentecostal chapel. There he listened to the pastor preach and a congregation moan and testify with unashamed piety. As both man and actor, Duvall was powerfully affected.

"It was the good feeling," he said. "There was a certain simplicity and understanding. And also the feeling of the folklore. Preaching is one of the great American art forms. The rhythm, the cadence. And nobody knows about it except the preachers themselves."