Best of the current period novel; Covenant of Grace, by Jane Gilmore Rushing. New York: Doubleday & Co. 392 pp. The Sea Beggars, by Cecelia Holland. New York: Alfred A. Knopf. 305 pp. $13.95 . Gilded Splendour, by Rosalind Laker. New York: Doubleday & Co. 238 pp. $16.95. A Chain of Voices, by Andre Brink. New York: William Morrow & Co. 525 pp. $15. 50.

Imagine a world in which religion was an issue as burning and important as nuclear war is today. That was America in the 17th century.

Into this fervent religious climate sailed Anne Hutchinson and her family in 1634, following preacher John Cotton to Boston. Anne's dream of spiritual fulfillment was threatened from the outset by Gov. John Winthrop and other political, as well as religious, leaders from the Massachusetts Bay Colony.

They believed in a covenant of works - good deeds as the only road to salvation. Anne Hutchinson, however, preached that grace was not dependent upon man's outward appearance, but upon the spirit of the Christ within: that is, a Covenant of Grace.

To her followers, this loving and lenient covenant of grace must have seemed like a breath of fresh air in the strait-laced climate of the Bay Colony. To Governor Winthrop and his supporters, she was an ill wind that menaced their vision of a holy city. To protect their dream, they attempted to destroy Anne's standing by charging her with heresy.

This is Rushing's first historical novel, but she handles it like a pro. ''Covenant'' is fictional historical writing at its best. The characters are inseparable from the period in which they lived. And the rich details give life to the people and their time.

The Sea Beggars is another excellent novel of religious persecution, this time set on the other side of the Atlantic in late 16th-century Netherlands.

The Dutch revolt against the Spanish was the precursor to a series of wars that eventually led to the American and French Revolutions nearly two centuries later.

In the Netherlands of the 16th century, Protestant sects flourished alongside Roman Catholicism, for the Dutch were a tolerant people. Trouble came, however, when Philip II, a fanatic Catholic, sought to extend the Inquisition into the Low Countries. He met with stubborn resistance.

Against this backdrop unravels the story of a brother and sister brought up as Calvinists in Antwerp. Jan flees before the invading Spanish and joins the Sea Beggars, a band of pirates who dare to plunder the Spanish Navy. Hanneke remains in Antwerp until she joins Jan at The Brill, where they fight the numerically superior Spanish army.

This is the 13th novel from a writer who has consistently gotten A's since she began writing in 1966 while still in college.

For those who prefer lighter reading, there's Gilded Spendour, a fictional romance about Thomas Chippendale, the 18th-century master furnituremaker.

The fact that little is known of Chippendale's life doesn't hinder author Rosalind Laker from spinning out an engrossing tale of romantic goings-on that has the cabinetmaker dividing his time equally between work and pleasure.

Amid these romantic fabrications, there are some enlightening descriptions of the exhausting and rigid procedures Chippendale used to craft only the finest furniture. The quality of Chippendale work was attested to recently when a Chippendale mahagony bureau brought $350,000 at a New York auction house.

The main flaw of the novel is that some of the purely fictional characters are more lifelike than Chippendale, who remains throughout as wooden as his furniture.

A Chain of Voices has received wide publicity because its author, South African novelist Andre Brink, is a voice against his country's policy of apartheid.

The author has a story to tell - how the injustice of one man owning another, master and slave, eventually leads to the downfall of both.

If the reader is to glean the good from this book, he must pick his way through a minefield of crude language and sexual vulgarities. Many may choose to avoid the book for that reason, for it is impossible to harvest the wheat without a heavy dusting of chaff.