On Saturday night, the National Philharmonic constructed a towering monument onstage. And just 30 minutes later, it was gone — scattered by a blast of applause.

The combined forces of the National Philharmonic Orchestra and Chorale, the Washington Chorus, members of the Howard University Chorale and a powerhouse trio of soloists filled the stage at Strathmore to premiere “A Knee on the Neck,” a bracing, captivating and essential new work for soloists, chorus and orchestra by composer Adolphus Hailstork and librettist Herbert Martin.

“America’s Requiem: A Knee on the Neck” paired this new requiem, composed in memory of George Floyd and other victims of police brutality, with a full performance of Mozart’s foundational Requiem in D Minor. And yet it was the former that left me with most to remember. (Mozart: not often upstaged.)

The massive gathering of choral singers onstage — 135 in all — was, first and foremost, a welcome sight and sound. It’s been years since I’ve been enveloped by the voices of a chorus this large. Good stuff. But the visual of this assembly had additional value in driving home the colossal emotional scale of this piece, which combines the intimacy of a church service with the ecstasy of a revelation.

Maestro Piotr Gajewski and chorus master Eugene Rogers (also artistic director of the Washington Chorus) admirably managed the onstage masses, attaining throughout the evening a well-balanced sound — music fraught with gravitas and lightened by grace.

Martin, a professor emeritus of the University of Dayton in Ohio, drafted the libretto for “A Knee on the Neck” within a week of Floyd’s murder in May 2020 and sent it straight to Hailstork. The two have enjoyed a long collaborative history together over the years, creating striking vocal works that directly engage history: a tribute to Martin Luther King Jr., a commemoration of the 1921 Tulsa Race Massacre, a cantata for Crispus Attucks, among others.

“A Knee on the Neck,” meanwhile, is in direct conversation with the present, carrying the immediacy of Martin’s libretto directly into the music — which faintly echoes the shape of a traditional requiem with its stationed progression, its embedded hymns, its calls, responses and refrains.

Hailstork inhabits the expectations of a traditional requiem in unexpected ways — allowing for constant movement and motion between the chorus and the soloists. A bed of rising, gathering strings whoosh throughout its opening stretch like a hard breeze through an open window, whipping around the stage. The effect was combustible. Under Gajewski’s hands, the orchestra surged now and then from candlelit prayer to roaring pyre.

The choral elements — and there were many — were also beautifully set. Choral music comes naturally to Hailstork, who started out in Albany, N.Y., as a boy soprano singing in choirs, and has spent most of his career composing works for chorus and orchestra.

Mezzo-soprano J’Nai Bridges (for whom Hailstork has previously composed), tenor Norman Shankle and baritone Kenneth Overton each gave splendid performances, each with moments of individual brilliance. But they were most beguiling when their lines were braided together, or swept up in dialogue with the colossus of the chorus.

Bridges was especially gripping throughout the performance, her mastery put to full use in the suite’s opening section, “A Black Mother’s Commandment” — a poetic distillation of “The Talk” given by Black parents to their children. She fully inhabited the anguish of a mother begging her son to “do what they tell you because they are the law at that moment,” but imparted to it an angelic glow.

Shankle was also fantastic, singing a searing a cappella that combines the perspective of a prisoner on mail day with haunting choral cautions: “Have you ever seen a knee on the neck? Chile, that stops all breathing ... Come on home.”

It was perhaps here, in the suite’s “Folk Song,” that the strength of Martin’s libretto could be felt in harshest relief. A poet’s poet, he’s a master of economy, choosing each word with the deliberate strike of a chisel. “Virus” becomes not only a historical marker of 2020, but also a metaphor for cruelty and hatred in contemporary American life that speaks to not just the loss of life, but also our loss of faith in one another: “There’s a virus going round taking names/ It has taken my neighbor’s name.”

Martin has also got a virtuoso’s sense of music, of which Hailstork takes full advantage: stretching single syllables into haunting scrims of sound — such as “Ma,” which becomes a devastating evocation of Floyd calling for his mother. Or the way Hailstork really has the chorus lean into those humming M’s of “come home” like the hinge of an amen.

The Requiem in D Minor saw the trio of singers joined by the stellar soprano Janai Brugger, whose tone glows with an entrancing balance of brightness and warmth. Her exquisitely sung introductory statement, the “Requiem aeternam,” immediately returned us to our regularly scheduled requiem programming.

And while the chorus truly found its footing on such familiar turf (even slightly reduced by the exit of the Howard singers), and the ensemble of soloists sounded equally at home, the NatPhil itself sounded a touch tuckered, frequently clouded over by the chorus rather than bathed in its light. The orchestra’s performance was crisp and sharp — some of the rhythms, as in the “Lacrimosa,” perhaps a little too strict — but despite movement and color galore, they were missing some pep. (Mind you, I’m not certain how much pep is appropriate to bring to a funeral.)

Perhaps it was just the contrast of its companion piece that accounted for this perceived dip in energy. Mozart’s Requiem lives so deep in many of our memories that it can be hard to hear it anew. Hailstork and Martin have created a requiem that feels alive and has only just taken its first breaths. It has something to say about the immensity and intimacy of pain — and we owe one another as Americans to listen.