Krzysztof Penderecki's "Polish Requiem," which had its first complete American performance last night at the Kennedy Center, begins and ends with words of comfort. "Requiem" ("rest") is the first word, sung softly and slowly by the chorus in simple octaves -- "Requiem aeternam" ("eternal rest") on a single note, C, repeated seven times.

At the end, the word is "vitam" ("life") sung fortissimo by the chorus and four soloists: "Free the souls of all the faithful departed; make them pass over from death to life."

In a bit more than an hour and a half, between those synergistic and contrasting moments, this music takes the performers and audience on a vividly dramatic tour of the terror, agony and guilt that have scarred the history of our time. But its final impact, true to the requirements of its text, is one of consolation -- all the more effective because it has looked without blinking at turmoil, violence, brutality and anguish. In its American premiere, with Mstislav Rostropovich conducting the National Symphony Orchestra and the Choral Arts Society, it sounded like a worthy successor to the great Requiem settings of Mozart, Berlioz and Verdi.

Parts of the Requiem are inspired by and dedicated to people who have figured in contemporary Polish history: Lech Walesa and his Solidarity movement; Stefan Cardinal Wyszynski, who was the bulwark of Poland's resistance to a Stalinist government in the generation after World War II; the Rev. Maximilian Kolbe, a Polish priest who gave his life at Auschwitz to save a fellow prisoner. Penderecki takes further steps to make this specifically a Polish Requiem by weaving a Polish hymn, "Swiety Boze" ("Holy God"), into some sections of the traditional Latin text.

But if this is explicitly a Polish work and one of the late 20th century, it is also timeless and universal. The emotions with which it deals -- the emotions embodied in the ancient Latin text of the Mass for the Dead -- are as old as humanity and have been experienced wherever people have lived and struggled. Penderecki crystallizes those emotions, intensifies them and embodies them in forms that communicate immediately, deeply and memorably. He has produced a classic treatment of the oldest text regularly set to music, a text that has already inspired more unchallenged masterpieces than any other.

The "Polish Requiem" is often virtuoso music, but some of its most effective passages are the simplest. In the "Dies Irae" section, which depicts the end of the world and is traditionally a showpiece for vivid orchestral and choral writing, Penderecki pulls out all the stops: spectacular percussion, gleaming brass and terrified scurrying in the violins; deep muttering in the bass strings and winds to illustrate nature's stupefaction as the dead rise from their graves.

Virtuoso avant-garde techniques, mastered early in his career, serve Penderecki well at such moments. His style has changed, but he has not abandoned the hair-raising techniques of his past; he has assimilated them into an essentially romantic orientation where, used with moderation, they deepen and intensify his expressive powers.

But some of the most striking moments are the simplest -- a solo oboe passage, for example, following the duet of soprano and alto in the "Recordare," which was beautifully performed last night. And the carefully tempered modernism of some passages is superbly contrasted in the "Agnus Dei," written for eight-part a capella chorus in a style whose roots go directly back to the Renaissance. It steps out of that style momentarily at its climax with three loud, clashing chords on the word "peccata" ("sins") which are marked to be performed as "quasi un grido" ("almost a cry") and then returns to the soft, calm invocation of the "Lamb of God." In its unadorned way, it is almost a microcosm of the tensions and contrasts in the whole work.

The first American performance of the full text was worthy of this outstanding music. Rostropovich has already given the world premiere of the complete work (with 14 sections rather than the eight performed here two years ago) in Europe. He has obviously studied the music in detail and feels it deeply, and his fervor and expertise were communicated well through the orchestra and chorus, both in top form. All the soloists were good. Bass-baritone Malcolm Smith had probably the most challenging assignments and filled them well. Soprano Phyllis Bryn-Julson and alto Jadwiga Rappe were excellent in solo passages but particularly impressive when singing together, and tenor Wieslaw Ochman sang with well-rounded tone and excellent control.