There was a moment at the Kennedy Center last night when a spark brought the capacity audience to life. The Edwin Hawkins Family Singers augmented by a sizable contingent of area gospel singers, filed on stage after intermission and grouped around three microphones: with the first bars of "Worship the Lord" and the exuberant swaying and clapping of the singers, gospel fervor entered the concert hall.

It was a sharp contrast to the consistently lethargic playing of the National Symphony Orchestra, which continues having difficulty handling pop under any circumstance. Being matched with Hawkins should have made it easy. His brand or gospel is as pop as BB King's brand of blues. "Oh, Happy Day" brought Hawkins fame in 1963; he has sustained a career with much less interesting but equally popular material, spreading a Christian gospel and reaping numerous awards. (Mayor Marion Barry declared yesterday Edward Hawkins Day in the District of Columbia.)

Last night's selections reflected the glorious voices of the Hawkins entourage without indicating particular talents on the part of the composers. The classical selections played by the NSO in the first portion were equally unimpressive, though the opening (and gloriously brief) bombast of "Celebration" by Adolphus C. Hailstork gave the momentary illusion of a lively orchestra. The detached professionalism of the NSO was, thankfully, overrun by the celebration of voices raised high in the second half of the program.