Nowadays if you ask a Bach scholar how many singers per part should be engaged in Bach's cantatas and Passions, you might get a dirty look; and if a debate should ensue, you might get a biff in the snoot and no apology.

It's still a divisive issue, in other words. It started in 1981 when Joshua Rifkin — conductor, Baroque scholar and ragtime pianist — put forth the notion that Bach's Mass in B Minor was originally performed with only one singer per part, and the same for the other big choral works, which meant that the traditional Bach choir, with its dozens, if not hundreds, of enraptured singers in choir robes, was a modern invention. Rifkin's main evidence: only one score per voice exists for these works.

Some colleagues guffawed and called this Rifkin's folly. Others took it seriously: Andrew Parrott for one, and, for another, Paul McCreesh, who is leading the St. Paul Chamber Orchestra in illuminating performances of the "St. Matthew Passion" at the Ordway Concert Hall this weekend.

Working with eight talented young singers from the Gabrieli Consort, an early-music ensemble, four singers per chorus, and an orchestra of about 30 players, McCreesh made a strong case for his — and Rifkin's — view of the work and how it is best performed.

There was no loss in vocal heft, for instance. The singers produced a full-bodied sound that belied their small numbers. And though his tempos were lively without feeling pushed — the crowd scenes, for instance, were delivered with special punch — the conductor managed to sustain the work's essential quality of introspection and repose. The static moments in this three-hour-plus meditation on Christ's waning hours and final agony are probably inevitable. On Friday night only the final half-hour or so seemed to drag.

Nicholas Mulroy was an excellent Evangelist, the work's narrator. With his wide-ranging, expressive tenor, Mulroy displayed a deep involvement in the story. It was as if he were a reporter on location, describing with growing urgency the scenes he was witnessing.

In a role so often sentimentalized, baritone Peter Harvey portrayed Christ as a down-to-earth, very human, at times perplexed visitor to this world trying to make sense of it all. Alto Paula Murrihy brought rapt focus and immaculate tone to "Erbarme dich," one of Bach's most ecstatically beautiful arias.

The others, all of whom contributed mightily, were Mhairi Lawson, Anna Dennis, Helen Charlston, Nick Pritchard and Matthew Brook.

Michael Anthony is a Minneapolis music writer.