This weekend (through Monday night) the National Symphony is performing Handel's "Messiah." There is no surprise in that; they do it at this time every year, and howling mobs might storm their offices if somehow they forgot.

Nor were there any surprises in last night's performance at the Kennedy Center: a solid, joyful, reverent and musically precise interpretation, fully worthy of this unchallenged masterpiece -- the classical composition most widely and deeply loved in the English-speaking world, and historically the first piece of music to establish itself firmly in the repertoire as a classic.

There was a last-minute substitution among the soloists: mezzo-soprano Wendy White for alto Gretchen Greenfield, who became ill. Very dramatic, particularly since White's plane arrived an hour late yesterday. But she was on time for the performance, and nobody unaware of the backstage drama would have guessed that she had not been rehearsing with the orchestra for days.

If there was anything to criticize seriously in the performance, it may have been the balance (musically, not in dynamics) between the chorus and the orchestra. Sometimes, it sounded as though the stylishly small orchestra was the guest of the medium-sized chorus from the Oratorio Society. The choral sections were hardest hit in the dozen numbers omitted from the performance, and it would have been good to hear what this outstanding group might have done with "And he shall purify," "He trusted in God" and "Lift up your heads." But even with these omissions, the chorus was clearly the star of the evening, light in tone, agile in phrasing, superbly expressive and precise in diction. One reason may have been that conductor Richard Westenburg is primarily associated with choral music, but he also handled the orchestra expertly. It was not that the NSO was bad, but that the Oratorio Society was so outstanding.

It was understandable that White produced one or two notes slightly below her best form at the beginning of the evening, but the problem was barely noticeable; even mentioning it exaggerates its importance. In fact, the only soloist who did not have an uncomfortable moment or two in her first number was soprano Sylvia McNair, who has the good fortune to start her night's work (unlike her colleagues) with a series of recitatives rather than a highly ornamented aria. McNair's voice has a fine clarity of tone, approaching but not going over into thinness in an auditorium the size of the Concert Hall. It contrasted well with the deeper, richer tone of White, particularly in their shared aria, "He shall feed His flock."

Tenor David Gordon, like all the voices in this well-balanced performance, was notable for clarity in tone and diction, as well as for his fine sense of baroque style and his proficiency in singing florid ornaments. The same was true of baritone David Evitts, whose larger voice faced the most serious challenge in the long, fast runs up and down the scale that Handel requires of his soloists. He met the challenge with distinction.

Still, the choral moments were the most memorable: the beautiful tone and smooth phrasing of the altos in the score's first choral entry, "And the glory of the Lord"; the splendid lilt of the sopranos in "For unto us a child is born"; the exemplary tone and balance of the tenors and basses throughout. The Oratorio Society's "Messiah" is a superb one, even with some of its potentially finest moments on the cutting-room floor.