"Say Amen, Somebody" deserves not just a shout of praise but a chorus of hallelujahs.

Inspired director George T. Nierenberg explores the rich lives of two American treasures, Mother Willie Mae Ford Smith and Professor Thomas A. Dorsey, in this toe-tapping, heart-rending revival meeting of a musical documentary. Built on the rock of ages and born of moody blues, gospel music, sung by Smith and Dorsey, is what they call God's good news. Their voices have started to wrinkle, but when they sing, it doesn't matter because there's so much feeling pouring through the cracks. To hear them is to feel your spirits soar.

The soundtrack of 25 songs performed by Dorsey, Smith and their proteg,es is superlative, rich and full. But Nierenberg's film is more than aural: It's an intimate work, with extemporaneous transitions that charm the socks right off you, sometimes leaving you crying or wishing you were over at Mother Smith's having some ribs.

Nierenberg, who researched his subject for a year before filming began, is not some liberal priss with a condescending view of charming lower-class folk. He's concerned, on the evidence of this movie, with the history of gospel, an expression of black culture -- a musical form 50 to 60 years old and derived from spirituals.

Dorsey, often called the father of gospel, now 83, was a blues composer known as "Georgia Tom" until he got the call in the early 1920s. His masterpiece, the moving "Take My Hand, Precious Lord," was written when his spirit was broken by the death of his young wife and child. "I just didn't know what to do or how to do," says the old man thinking back. And then, he recalls his despair and how, right then and there, he sang "Precious Lord" word for word just as it is to this day. His quavering first quatrain segues into a recording of Mahalia Jackson's version.

Mother Smith never had the fame of a Jackson, and her contralto voice, rich and ecstatic, wasn't recorded until she was 68 years old. Her fervor and her charismatic preacher's ability to transport her listeners make her one of the all-time greats. Her stories, recollections, the interactions with her family and disciples are intimate, amusing, deep and pure.

Nierenberg's film is a communion of spirit among director, principals and audience. As the gospel singers consecrate a convention hall for the opening night, they prepare a table with an open Bible, paper roses and plastic bottles of what looks like Vaseline Intensive Care Lotion for anointing the choir. In the hands of these believers, the mundane becomes sublime. Intensive Care becomes a holy balm.

"Say Amen, Somebody" is quite simply one of the best films of the year. SAY AMEN, SOMEBODY -- At the West End Circle. A review of the soundtrack appears on page 41.