In the middle of Saturday night's concert by the Boys Choir of Harlem, the ensemble's director, Walter J. Turnbull, told the audience, "If you feel the spirit, you have to move." Not feeling the spirit while watching and listening to this 32-member group was just about as impossible as staying in your seat in the Kennedy Center Concert Hall by the end of the 2 1/2-hour concert. This was a highly musical, energetic and very moving performance by a winning group of talented kids.

Turnbull included music from Mozart and Gershwin to Stevie Wonder and rap in the second of two concerts the choir gave Saturday. All the singing was powerful and disciplined, the words clear and the entrances almost always clean and together. What's more, this is a group of pretty sharp dancers, and their performances of choreography by Luther Fontaien, for the popular music in the second half of the program, were smooth and irresistible. A setting of "Mr. Bojangles" was especially charming, as was a boisterous medley of Ellington music, including "It Don't Mean a Thing (If You Ain't Got That Swing)."

Special praise is also in order for tenor Jason Oby's golden-toned solo work in "I Lift Up Mine Eyes," a cantata by Adolphus Hailstork. Oby, a vocal teacher at the Choir School, has a first-rate sound: sweet, accurate and flexible. He's a real pleasure to listen to.

The Boys Choir closes its concerts by leaving the stage to greet the audience; at the end of this performance, after the students finished a rap song on the "Joy of Singing," the boys ran up the aisles to the lobby. It was one of the most spirited finishes to a Kennedy Center Concert and marked the end of a joyous evening.