Leave it to Leonard Bernstein to induce ho-hums by announcing that he'll play an all-Brahms concert and then to confound everybody by putting on a Brahms program that is one of the liveliest, and most enterprising, of the National Symphony's season. That is what he did last night at the Kennedy Center, and there will be three repeats this week.

None of the standard Brahms was heard. There were no symphonies, no piano concertos, no violin concerto, no Haydn variations. The closest it came to the mainstream was a performance, at the same time both mellow and electric, of the Double Concerto, with violinist Gidon Kremer and cellist Mischa Maisky. Maisky, like Kremer, is a Russian e'migre', and he played with tremendous dash last night. If he was not quite the complete musician that Kremer is, that should count for little, because few are. Kremer's phrasing was at its most aristocratic and his sound was gloriously pure.

In the concerto the orchestra played superbly under Bernstein. The pulse was strong and steady and the attacks were precise. Yet there was real breadth and tonal variety.

The three works that came before the concerto were probably unknown to many in the audience. There was at first the grim, sober choral song "Gesang der Parzen," a setting for a song of the fates from Goethe's "Iphigenia in Tauris." The orchestra set the moody scene with passion and clarity before the Choral Arts Society began singing the six pessimistic stanzas. Bernstein was especially careful to keep Norman Scribner's choir quiet, except for one great outburst. The soft singing and playing at the end was especially beautiful.

To balance out the pessimism, Bernstein inserted afterward five of Brahms' orchestrations for large choir and orchestra of his popular Liebeslieder Waltzes. Bernstein played them very broadly, with tremendous lilt. Despite the size of the forces, the works managed to retain their nimble grace as Bernstein reined in the sound, keeping it very light.

Finally, there was Brahms' youthful A-major serenade. It really is more a chamber work that sounds a bit like the Schubert Octet than a work of symphonic scale. Brahms banishes the violins, so that the lower strings support the winds, which carry the main lines. As he did throughout the evening, Bernstein took a very leisurely view. All the winds played very well, and the horns, in particular, were in fine, rich form.