Today's sermon concerns the evils of ambition. It is a tale of a fine community orchestra that bit off more than it could chew. The Fairfax Symphony Orchestra filled the Kennedy Center Concert Hall Saturday evening with what could be called provincial sounds. And the news from the provinces is not good.

When not played brilliantly, Strauss' monumental "Thus Spoke Zarathustra" can be long-winded musical apology for a premature climax. On Saturday even the famous introductory 22 bars lacked power, plagued not only by timid percussion and erratic tempos, but also by a marked absence of a point of view. Elsewhere the violins were less than lush and the lower strings lacked homogeneity. There was even what sounded like hillbilly fiddling from the solo violin in the "dance Song." The playing was often as thick as the German prose that inspired the work, but far less profound.

Rachmaninoff's Concerto No. 3 is living proof that music need not be avant-garde to be valid, and even in this concert there were moving moments. But much was due to the composer, in the same way that even a mediocre performance of "Swan Lake" will elicit goosebumps at the close. Roy Hamlin Johnson showed a powerful but often careless piano technique, a sort of heroic voice that stuttered too often.

A "Marche Militaire Francaise" opened the program. It was unusual enough to discourage comparisons and light enough to fall within the powers of the ensemble. The Fairfax Symphony should play more such pieces.