Monday evening’s choral-orchestral extravaganza delighted and exalted a substantial Gaillard crowd with three spiritually potent masterpieces. In this annual event — long a cherished Spoleto USA highlight — the Westminster Choir (WC) and the Charleston Symphony Orchestra Chorus (CSOC) join forces to form a meaty mega-chorus. Along with members of the Spoleto Festival Orchestra, the conjoined choirs (prepared respectively by their directors, Drs. Joe Miller and Robert Taylor) fill the Gaillard stage to overflowing year after year, resulting in the festival’s single biggest event — at least in terms of the sheer numbers of performers. Holding these sprawling forces together from the podium is Dr. Joseph Flummerfelt.

The evening’s program began with one of Johannes Brahms’ loveliest creations in the genre: his fairly brief Alto Rhapsody, for alto soloist and male choir, written at about the same time as his well-loved German Requiem. While not a true sacred work, it’s indeed a highly spiritual one, reflecting (as does the Requiem) the fact that Brahms was a deeply spiritual man. After all, the work sets a text by German master poet J. W. von Goethe (also not a conventional believer) that chronicles a lonely wanderer’s bleak winter journey and sharp longing for respite and comfort.

The piece’s scoring for solo alto and male choir reflects Brahms’ penchant for dark-hued lower sonorities: something we hear in many of his works. Here, the darkness of the sound — along with mezzo soloist Margaret Lattimore’s initially anguished tone as she bemoaned the wanderer’s sad desolation — resulted in a sharp emotional downer, as the composer intended. But — as the chorus’s men stood and joined her, the music melted into a disarmingly lovely evocation of sweet solace as they seemed to pray together to the “Father of love” to send the sufferer a “single tone” from his Psalter to relieve the wanderer’s suffering. It was one of the concert’s most incredibly moving moments. Lattimore impressed mightily with her lush and emotion-laden voice, and the men’s mostly soft, yet rich-toned singing did much to bring out the prevailing sentiment.

Our artists treated us next to Leonard Bernstein’s Chichester Psalms, commissioned by the Dean of Chichester Cathedral in Sussex, England, and composed in the mid-1960s. A big part of Bernstein’s compositional legacy is that he was perhaps the first composer to not only bring classical complexity and depth to the Broadway stage, but also to infuse his classical creations with Broadway’s jazzy jive. With most of his time devoted to conducting, Bernstein was a keen observer and analyst of prevailing compositional styles and movements. While he didn’t hesitate to draw from any musical style that suited his creative purposes, he rarely strayed from his conviction that his era’s preoccupation with 12-tone complexity and atonality detracted from music’s essential purpose of delighting the ear and exalting the spirit.

Thus the Chichester Psalms. The work encompasses many of the musical trends of his day, yet remains tuneful and accessible to most ears, presaging the 21st century’s return to the basic recipes of pure melody and diatonic (or modal) harmonies that have worked for over a millennium. Still, you’ve got to wonder what the Chichester Dean must’ve thought about presenting Bernstein’s often modal treatment of Hebrew texts, laced with jazzy syncopations and bongo drums, to his staid and tradition-minded Anglican parishioners.

Flummerfelt and company immediately got into the music’s eclectic spirit, realizing its assorted stylistic impulses effectively while preserving the work’s basic sense of sacred unity and purpose. Whether the music was joyous and celebratory (Psalm 100), serenely reflective and worshipful (Psalm 23), or poignantly pleading for peace and brotherhood (Psalm 133), our performers remained true to the composer’s design and intent. Boy treble Peter James Schoellkopff negotiated his part with sweet-toned serenity — though he had to be subtly miked to insure that he was heard over the massive forces onstage. The four other “bit-part” soloists delivered their lines effectively from the composite choir’s ranks. The orchestra members had obvious fun with Bernstein’s irrepressibly freewheeling and spicy instrumental devices.

After halftime, we heard Austrian master Anton Bruckner’s Te Deum, his colossal choral paean of praise. Among the most spiritually potent, yet humbly self-effacing of all composers, Bruckner’s style — much influenced by Wagner — was unabashedly grand and glorious, resulting in huge and granitic sonic monuments to his deity. Even his massive symphonies were written “to the glory of God.”

Flummerfelt and his musicians simply soared in this wondrous music, building gradually, often by chromatic steps, from quiet beginnings to huge climaxes. Of the four soloists, tenor Noah Baetge got the most moving and spine-tingling lines, and he executed them to sweet and spiritually devastating perfection. Soprano Rebekah Camm, double-duty mezzo Margaret Lattimore, and bass Eric Jordan left nothing to be desired. Chorus and orchestra alike unleashed massive, glowing gushes of sound. I’m glad they changed the event’s original order of performance to put this work in the final position, as it was by far the best way to bring this marvelous concert to a memorable close.

Hearty and heartfelt thanks, Dr. Flummerfelt, for seeing to it that we don’t have to journey to New York, London, or Vienna to hear choral-orchestral performances of such rare caliber as this.