On Saturday night at the Kennedy Center, the Millennium Stage hosted an unusual event: the world premiere of an unknown work by a neglected African American composer. Margaret Bonds’s Easter cantata “Simon Bore the Cross,” is set to texts by Langston Hughes. The same night, the National Philharmonic, at Strathmore, performed one of the most beloved works associated with the African American community: “Porgy and Bess,” written, of course, by a white composer, George Gershwin.

Both works represent attempts to fold the African American experience into the Western canon. Bonds and Hughes’s Easter cantata, which was found in a box of papers by a dumpster some time after Bonds’s death in 1972, followed their Christmas cantata, “The Ballad of the Brown King”; both focus on the rare stories of black characters in the Bible. (The brown king is Balthasar, traditionally represented as the African member of the three Magi who came to honor the infant Jesus; while Simon is Simon of Cyrene, who helped Jesus carry the cross on the way to Calvary.) And “Porgy and Bess,” of course, is a well-meaning attempt to elevate the black experience into the realm of opera.

If Bonds is known at all today as a composer, it’s mainly for her arrangements of spirituals, and one of her goals was to get her music to as wide an audience as possible. Her cantata, therefore, deliberately embraces the vernacular, laid out in seven clear, colorful musical episodes (including a radiant aria for solo soprano, “Who Is That Man?”) all interlaced with motifs from the spiritual “He Never Said a Mumbling Word.” The Georgetown University Concert Choir, which performed on Saturday, will be singing the piece again in April with different soloists, including the soprano Marlissa Hudson; she couldn’t sing with the group on Saturday because she was across town singing “Bess.” The choir will surely have the work more solidly in their voices by April; on Saturday, they were able to give the outlines of a piece that shows potential and should be taken up by more choruses.

As for “Porgy and Bess,” it’s a work of massive ambition and breadth, and it was probably wise of the National Philharmonic to cut its Wagnerian length roughly in half and focus on the most familiar scenes in its “concert opera” version.

Despite the composer’s protestations that “Porgy” is a “folk opera,” the score is quite sophisticated, and no easy thing to play. It’s to conductor Stan Engebretson’s credit that the Philharmonic performed with such confidence and élan. Perhaps, though, they showed Gershwin’s score too much respect, rarely conveying the music’s full sizzle and swing. The vibrant opening was a polite affair, the hurricane never intensified beyond a Category One, and the Philharmonic Chorale sang with careful diction and pristine phrasing that would not have been out of place in a Mendelssohn oratorio.

What theatrical verve came across was thanks to the soloists. Director Michael Bobbitt’s spare yet effective staging created more than a whiff of Catfish Row, and drew three-dimensional characterizations from the strong soloists, even in formal concert dress.  

Soprano NaGuanda Nobles’s Clara — the role given the inestimable advantage of opening the opera with “Summertime” — was sung with luscious, luminous tone, and as Serena, soprano Aundi Marie Moore brought searing conviction to “My Man’s Gone Now.” The part of Sportin’ Life is written for a natural showman. But Chauncey Packer, boasting a clarion tenor and high-kicking strut, found ample opportunities to also suggest the dangers lurking behind the drug-dealer’s easy smile.

With his elegant delivery and gently rolling bass-baritone, Kevin Deas emphasized the basic decency and civility in Porgy. There was a powerful Crown from Michael Redding, and solid work (in a variety of roles) by Edward Pleasant and Colin Eaton. Only Hudson, as Bess, disappointed — not in the lovely shimmer of her upper register or in her effective acting, but in her inability to adequately project her unmiked voice (especially at the lower end of her range).

Gershwin insisted that “Porgy” be cast exclusively with African Americans. It was instructive on Saturday to look out at the overwhelmingly white membership of the orchestra and chorus, striving for literalness and accuracy in their playing, while a group of prodigiously gifted black singers made this great American opera actually live and move us.

Simon Bore the Cross will be performed again at the Davis Performing Arts Center at Georgetown University on April 30.