Joy was the keynote at the First Baptist Church last night when friends of the Washington Chamber Orchestra donated their talents to present a gala evening of music. Under the honorary sponsorship of Rosalynn Carter, the concert was held to celebrate and support the orchestra's invitation to participate in the millennial celebrations of the city of Brussels.

The tour has been almost totally underwritten by the Belgian hosts. Last night's concert, which raised more than $14,000 in contributions by mail alone, will supply the remaining funds needed by the orchestra to make the trip.

The Washington Chamber Orchestra can count itself fortunate in having such a bevy of talented and helpful friends. The city of Washington can also take some pride in the quality and variety of musicians now resident in this area.

The program was a tasteful mixture of instrumental and vocal music from a wide range of artists, some well known, others still finding their path. After raising himself to the right attack height with a hastily borrowed hymn book, 16-year-old pianist Glenn Sales confidently started the evening off with some Liszt fireworks.

Soprano Chrissellene Petropoulos brought some dazzling fireworks of her own to several Verdi selections, tossing off the coloratura passages with the greatest of ease and agility. She teamed up later with flutist William Montgomery for an expressive performance of Herman Belinski's lovely setting of Psalm 23.

Two songs by Russell Woollen were given an expressive reading by tenor Douglas Robinson, with the composer at the piano. Appropriately, one of Washington's most respected musicians, Paul Callaway, brought the festive proceedings to a mighty close with the glories of a Franck Organ chorale.