It’s difficult to picture the greatest composer of all time as a harried employee, struggling to haul his magnificent creations up a mountain of bureaucratic indifference. Yet the few letters left behind by Johann Sebastian Bach reflect just that picture; more often than not, they are pleadings for a better position or for compensation promised. His attempts to secure a more favorable situation – as in 1717, when he abandoned Weimar for an offer in Cothen – actually landed him in jail.

By late 1725, now in Leipzig and embroiled in the usual feuds, Bach seemed to grow weary of it all. His output of new pieces decreased, and he increasingly fulfilled his church obligations with cantatas by his cousin, Johann Ludwig Bach. Nevertheless, by Good Friday of 1727, seeing “a significant phase of his life drawing to a close,” in the words of musicologist Joshua Rifkin, Bach “took the occasion to produce a work that would synthesize and surpass all that he had previously done.” The “St. Matthew Passion” became the musical shot heard ’round the world.

This dramatic telling of the suffering and death of Jesus is monumental in scale, with scoring for two choirs and two orchestras, and a libretto by poet Christian Friedrich Henrici (who wrote under the name Picander). Nearly a century later, Felix Mendelssohn received a copy of the score (revised by Bach in 1736) as a gift from his grandmother and, after five years of preparation, presented it in Berlin in 1829. Thus was launched the great Romantic Era Bach revival.

Conductor Andrew Parrott and the original instrument group The New York Collegium will present the “St. Matthew Passion” this Thursday and Friday at St. Ignatius Loyola Church. The experience will be considerably different than the one offered by Mendelssohn, however. In place of the large orchestral forces and huge choruses most listeners in the 19th and 20th centuries came to associate with the work, this “St. Matthew” will reflect recent scholarship on the way it was done in Bach’s day. Most strikingly, the chorus will consist of only one singer per part.

The evidence that Bach actually used individual soloists for the choral parts was first trumpeted by Mr. Rifkin in the 1980s, and proponents and opponents of this approach have been battling ever since. Mr. Parrott’s book, “The Essential Bach Choir,” puts him squarely in the Rifkin camp. “Temperamentally, I was never a novelty seeker,” he told me recently. “But when I read Joshua’s work it seemed to me almost a duty to investigate the matter, and to see whether it stood up historically and what it would mean to performers. I found that the music was translated into something equally, if not more effective.”

Those who object to such a rendition do so on the grounds that the smaller forces remove some of the majesty of the work. Yet, a large chorus will produce a different color than an individual voice, but not necessarily much more volume. “One person may have a majestic bearing,” asserts the British Mr. Parrott. “There is, after all, only one majesty on our throne at any one time. The sort of grandeur we associate with this music is from the Mendelssohn tradition onward. But I’m interested in finding what made the work majestic to Bach.”

To explain how this approach may change the character of the piece, he points to a review in Early Music Magazine of a recording with similar forces led by Paul McCreesh. During the trial scene, the critic suggested, a large chorus conveys the impression of a ferocious mob. With individual singers, on the other hand, we can become aware of the humanity and fragility of the participants, and imagine ourselves part of the crowd.

Daniel R. Melamed, whose forthcoming book, “Hearing Bach’s Passions” (Oxford University Press, 192 pages, $24.95) investigates these issues further, will be giving a pre-concert lecture to place them in context. Though we regard this work today as a dramatic presentation, he told me, in Bach’s time it served as religious instruction – a more intimate kind of musical sermon on which to reflect.

The New York Collegium, whose past outstanding performances put it in good stead for this task, also gave a concert last night at the Metropolitan Museum of Art in conjunction with the exhibition of drawings by Peter Paul Rubens. Creating such programs is an ever-expansive experience for Mr. Parrott, as listening to them no doubt will be for audiences. “I have discovered how much fun it is to stretch the boundaries of what we know,” he explained. “Exploring and experimenting helps us to find a way for these pieces to speak to us more directly across the centuries.”

The New York Collegium will perform Bach’s “St. Matthew Passion” March 3 & 4 at 8 p.m. at the Church of St. Ignatius Loyola (980 Park Avenue, at 83rd Street, 212-717-9246)