THIS NOVEL, like life itself for Afro-Americans in the post-Bakke 1970s, is an anguish-provoking experience in backward time travel. Its sincerity is unquestionable, its eloquence seductive - but its message is even more regressive than the many setbacks from the gains of the '60s that blacks have suffered in this Second Reconstruction.

Appropriately, Words by Heart is set during the closing years of the First Reconstruction. In 1910, we travel with Lena, a 12-year-old memory whiz, and her family on a journey from hope to despair. Her Papa Ben's fatal optimism has led them from the circumscribed safety of an all-black southern community, Scattercreek, to seek wider opportunity in an all-white western town, Bethel Springs, which he says "is big, open country with room for everybody." Papa Ben has assured them that Bethel means "welcome," and Lena's three small half-siblings are too young to doubt his word, but step-mama Claudie has trepidations. With each chapter of the novel, it becomes clearer that Claudie is right, and that the the towns' names, with their respective suggestions of scattering and welcoming, should have been reversed.

It is the words of the Bible that Lena has learned "by heart" - or at least by rote - at the beginning of the novel. And it is this magic memory that sets off a series of increasingly sinister events that make the welcome of Bethel Springs seem about as warm as the South Pole. Soon after the family's arrival, Lena makes the tactical mistake of competing against the community's white youngsters in a Bible-verse reciting contest - and winning. Her reluctantly given prize, a bow tie pre-purchased for the white boy who was supposed to win, makes it clear that she has really lost.

The most puzzling and distressing aspect of Lena's character development is that she begins as a proud fighter and ends as a model of meek Christian forbearance, exactly, as Claudie observes with resignation, like her saintly father. The Bible contains, along with everything else, counsel for both modes of behavior, making Lena's transformation from sword-wielder to cross-bearer especially difficult for this reader to accept. She has learned her verses under Papa Ben's tutelage, of course, but early in the book, to his reminder that" 'The Lord commanded, Thou shalt not kill,'" she re*sponds quickly, "But Papa, in the very next chapter Moses says anybody that smited a man and killed him surely die."

How Lena comes to learns Papa's favorite verses and not her own "by heart," in view of all the evils that beset her family, is unaccountable. One threat to their safety is the capricious nature of their employer, Mrs. Chism, a wealthy old dragon of a landowner who suffers unpredictable attacks of decency. She is perhaps the most complex and intriguing character in the book, but if she and people like her were consistently cruel, Lena, her family and the rest of us would be better off. Mrs. Chism is, for instance, too softhearted to get rid of her shiftless, dishonest poor white tenant farmers, the Haneys, who are incapable of anything but harm, until too late.

That Lena is able to feel sympathy for the Haneys at points in the novel, in spite of the threat they pose to her family; that, at the grim ending of the final and most suspenseful chapter, she decides to follow her father's dictum to "Love thy enemies and do good to them that hate you" is both appalling and incredible. One of the author's best phrases is: "Something always comes to fill the empty places . . . Something comes to take the place of what you lose." But if Sebestyen's brand of meek, turn-the-other cheek Christianity is supposed to fill the voids left by Malcolm and, yes, Martin, then we blacks and our youngsters will be in even deeper trouble.