In a city teeming with fine choral ensembles, Coro Allegro, under the direction of David Hodgkins, occupies a unique and distinguished position. It is Boston’s only mixed chorus for members and friends of the gay, lesbian, bisexual, and transgender communities dedicated to “building social and musical bridges through high-quality performances of significant choral works.”

On Sunday, November 15, at Sanders Theater, Coro Allegro presented a program of highly contrasted works: Five Mystical Songs of Ralph Vaughan Williams, Cantique de Jean Racine by Gabriel Fauré, and the premiere performance of the expanded oratorio Shofar by Robert Stern with libretto by Catherine Madsen. Sanford Sylvan, the soloist slated to appear for the Mystical Songs, unfortunately was stricken with the flu and could not appear. However, we were fortunate that Shofar features two bass-baritone soloists, and one of them, Donald Wilkinson, was prevailed upon to take Mr. Sylvan’s place in the Mystical Songs.

Mr. Wilkinson deserves our thanks for his yeoman service, singing the Vaughan Williams with a wide range of expression and mood. If his tone very occasionally became effortful in the highest reaches, due to the singer’s unstinting generosity of expression, it must be acknowledged that the five songs are better suited to a high baritone. Regardless, the performance had much to commend it. At virtually any given moment the orchestra soloist, and chorus, with consistently clear enunciation, were responding to the magnificent poetry of George Herbert. The strings made a particularly silken sound in the postlude of “Easter,” the pulsations of  “I Got Me Flowers,” and the erotic final section of “Love Bade Me Welcome.”

Mr. Wilkinson delivered an impassioned rendition of the non-choral fourth song, “The Call,” the very quintessence of Vaughan Williams’s style with its ever-lengthening melismas as the drama (and vocal line!) climb ever higher. The fifth song, “Antiphon,” is a breathtaking tour de force evoking pealing bells; its perpetual-motion accompaniment only occasionally relents — at each emphatic iteration of “my God and King” as well as in the ecstatic postlude. The fine orchestra never failed to listen to Mr. Wilkinson, the chorus, and, not least, each other.

The long choral lines of Cantique de Jean Racine of Gabriel Fauré made one admire the pleasing balance the chorus achieved between warmth (i.e., vibrato) and purity of blend; and dynamics throughout were impressively nuanced. As a choral veteran, your reviewer can attest that even talented choruses find gradual diminuendos considerably more challenging than crescendos; all too often a composer’s request for an extended tapering-off results in a rather dramatic, sudden plunge in volume. Coro Allegro provided a fine example of what concentration and practiced control can achieve.

The main event of the concert, the oratorio Shofar, is a large-scale work for soprano, tenor, two bass-baritones, chorus and orchestra. To quote its librettist, Catherine Madsen, “The shofar is the ram’s horn of Jewish liturgy, used during the High Holy Day period to evoke the breakdown of the soul’s defenses against the consciousness of sin and bring about its return to God.” The four sections of the libretto correspond to the four types of shofar blasts used in liturgy which are also metaphors for humankind’s changing relationship with God: Tekiah, a long unbroken blast signifying wholeness; Shevarim, “broken,” a triple blast; Teruah, “smashed,” a nine-fold stammering blast; and Tekiah G’dolah, a very long blast signaling the return to wholeness. The libretto is a mixture of passages from the Hebrew Bible (mostly in English) and late-20th-century poetry.

The first section ( “Whole”) opens with the chaos of creation which resolves into wholeness. The excellent tenor soloist, Jason McStoots, is introduced as a sort of participating narrator, not unlike the Evangelists in the Bach’s Passion settings. There follows a fascinating dialogue between God, nobly voiced by bass-baritone David Kravitz, and the people, represented by alternating men’s and women’s choruses. The people and God talk at each other but don’t communicate. Nonetheless, the dialogue leads into an exquisite love duet (“I am my beloved’s and my beloved is mine”) between the tenor (Mr. McStoots) and the soprano, Teresa Wakim, which is interrupted by the breaking in of the next section.

The second section (“Broken”) tells of Moses’ delayed return from the mountain and the consequent making of the golden calf and breaking of the tablets; it literally calls for musical hedonism which Mr. Stern ably provides. The celebration of the golden calf is led by Ms. Wakim, in one of the most delicious passages of the score. Unfortunately, here were the only instances in the concert when balances went briefly awry: Ms. Wakim’s radiant lyric soprano was swallowed up by the chorus and orchestra at several climaxes of the hearty celebration. The bacchanalia is interrupted by the delayed appearance of Moses, sung with authority by Donald Wilkinson. The section ends with God’s brokenhearted lament: “The misery of love as a father weeps [for] a child he cannot love,” which Mr. Kravitz sang with beauty and pathos.

In the third section (“Smashed”) God’s mood shifts from sorrow to rage as he promises to withdraw his protection of his people and their descendants. Along with Mr. Kravitz, the principal cellist and subsequently all the celli deserve plaudits for their vivid virtuoso depiction of fury.

The final section shows the return to wholeness through a renegotiated covenant between Moses and God, which culminates in a duet, first in Hebrew, then in English: “God merciful and gracious, slow to anger, full of kindness and truth …” The chorus then returns in something resembling a final chorale in one of the Bach Passions. We hear a reprise of the love duet, and the orchestra builds to a stunning final chord composed of stacked tritones. Here one must put aside any Christian notions of what the tritone represents and take it, first, for its literal imitation of the sound of a shofar and, second, as a representation of both the strength and instability of the relationship between humankind and God. Ms. Madsen’s description could well sum up the oratorio as a whole: “[F]rom this inner compulsion — at the realization that God can have no better people and the people no better God, and that the relationship cannot in any case be annulled — desire and consummation emerge: the gravitational pull between the visible and the invisible, the perfect and the imperfectible, the ephemeral and the eternal, working together for a brief time in the ecstatic concord of lovers.”

Mr. Hodgkins, the excellent quartet of soloists, Coro Allegro and its superb orchestra, the composer, and the librettist received a well-deserved standing ovation. We are delighted to learn that theywill be recording Shofar early in the new year, and we expect the audience for this 21st-century masterwork will be greatly expanded in short order.

Geoffrey Wieting holds Bachelor’s degrees in organ and Latin from Oberlin College and a Master’s degree in collaborative piano from New England Conservatory. Currently, he sings in the choir of Trinity Church and accompanies the Boston Choral Ensemble under Miguel Felipe.