"CHILDREN OF the Heav'nly King: Religious Expression in the Central Blue Ridge," a two-record set produced by the Library of Congress, is a fascinating piece of Americana and a vivid cross-section of traditional modes of religious expression in that predominantly Baptist region. It's also a reminder of the kind of bedrock faith that people tend to overlook in these days of the Electric Church. The simple, eloquent rural voices heard here, hearts and minds speaking so directly to God, form a marvelous humanist quilt. It is the musical equivalent of primitive folk art.

Charles K. Wolfe has written an enlightening essay that defines the parameters of the "public celebration and private testimony" that exist on "Heav'nly King": "congregational or group singing, preaching, extemporaneous testimony, prayer . . . communion services, baptisms, weddings, revivals, association meetings, funerals . . . all are part of the fabric of traditional rural life in the central Blue Ridge, where religion still plays a highly visible and dominant role in most people's lives."

Four years ago, a team of folklorists and photographers lived in the region for two months, observing, absorbing and recording the church-centered activities that dominate community life. The resulting records are not just about music, or even about faith, but about the way faith can encompass and encourage everyday life. Many Blue Ridge churches are small, encouraging individual participation in services, creating a spontaneity and warmth that's lacking in much church music. The listener doesn't even need to be a believer: as one elder says of another gospel figure, "I don't believe his doctrine but I sure like his singing."

There is an engaging variety of styles on "Heav'nly King," from the country duet of the Elk Horn Four's "On the Other Side of Jordan" to the primitive Baptist hymn, "A Home in Heaven" (sung a capella by Elder and Mrs. Jess B. Higgins of Galax, Va.), from the exuberant evangelism of Rev. Fred Akers' "What a Time We're Living in" to the lined-out "Must Jesus Bear the Cross Alone," where a church elder chants out the lines of the hymn before the congregation sings it. Hymns are sung in unison, sometimes in parts, sometimes with harmonies (the natural, unintentional ones that create a "heterophonic effect"); they are almost always sung in their entirety, not just three verses and out. The tempi vary as well, from a slow and stately title cut that sounds as if it were recorded when it was written 200 years ago, to the more lively and emphatic "Satan, Your Kingdom Must Come Down." In almost every instance, the songs come from ancient hymn-books that have been handed down conscientiously from generation to generation.

With its evocative pictures and explanatory text contained in a 46-page booklet, "Heav'nly King" functions as a visual documentary. One can almost be there for the baptism by the creek, be there in those most intimate moments when people talk about how they came to religion, and in some cases, to the ministry. The sermons, half-sung and half-shouted, wholly hypnotic, are fascinating as well. ("Children of the Heav'nly King" is available for $14.95 from the Recording Laboratory, Library of Congress, Washington D.C. 20540.)

Washingtonian Helen Bonchek Schneyer also has put out an album dominated by the exuberant strains of Baptist hymns. "On the Hallelujah Line" (Folk Legacy FSI-85) is a collection of religious music drawn from sources as diverse as A.P. Carter, Albert Brumley and the black gospel tradition. Schneyer, a longtime figure in Washington's folk community who also has worked with composer John Cage, has become better known recently through her frequent appearances on "Prairie Home Companion." She has one of those grand, natural voices that come along every 10 years. It is a voice that is neither sweet nor rough, but thoroughly accessible and honest. As Garrison Keillor points out in his moving liner notes, Schneyer "would be restless singing small, intimate songs . . . it's natural she should be drawn to hymns, the most powerful songs we have."

"Hallelujah Line" has its share of soul rattlers, but for the most part what's striking is the intimacy with which Schneyer imbues songs like the mournful gospel tune "My Father, How Long" and the joyful "The Sweetest Words He Ever Said." She accompanies herself on the piano with turn-of-the-century simplicity that emphasizes the basic elegance and strength of the melodies. Schneyer carries the main load, but she's often joined in chorus by her daughter Riki, or Cathy Fink and Jonathan Eberhart, all of whom have a great affinity for the material.

Other highlights include "Fountain Filled With Blood," which tempers religion with political activism over working conditions in the mines, and the good-natured outreach of "Meeting in the Air" and "Shine for Jesus." There's another quality about Schneyer's recording, what can only be called a living room ambience: there is no discernable distance between the playing of record and the hearing of it. Close your eyes, and Schneyer is there, leaning into her song, shaking her head with affirmation, singing good and loud and honest to God.