SOME OF the best and brightest fabrics being produced today grow out of a Judaic textile tradition that can be traced unbroken back to Old Testament times.

Some delightful evidence of the undiminished vigor and inventiveness of the modern practitioners of this ancient art can be seen in the current exhibition at Washington's B'nai B'rith Klutznick Museum, which features the work of a score of artists currently working in the United States.

While some workers still hew strictly to the specifications laid down in the Old Testament (attach a cord of blue to the fringe at each corner . . . look at it and recall all the commandments of the Lord), others synthesize Jewish and secular themes.

Margo Irwin of Radnor, Pennsylvania, for instance, executes exquisitely stitched samplers that would be the envy o any Pennsylvania Dutch seamstress. In the dense, rich weavings of Washington's Lizou Fenyvesi, which tease the eye with the suggestion of a fourth dimension, all themes are subordinate to a firm artistic conviction.

It's a refreshingly bright and airy show, particularly because the Klutznick, as a museum devoted to the Jewish experience, necessarily often deals with somber-to-horrific themes. "We certainly are delighted with the change," said director Linda Altshuler. "Our docents love it, too; this is something they can smile about."

The design of the exhibit is another small wonder by Chris White, who should be designated as a local if not national artistic treasure.

VESTMENTS AND VISIONS: JUDAIC TEXTILES --

Through September 13 at the B'nai B'rith Klutznick Museum, 1840 Rhode Island Avenue NW. Open Sunday through Friday from 10 to 5. Docent-guided tours at 11 and 1 Tuesdays, Wednesdays and Thursdays; for special arrangements, call 857-6583.