Bach, Biber, St. John's Smith Square. Clever juxtapositions, and they worked. The programmer of this concert - by the Monteverdi Choir and English Baroque Solists under Sir John Eliot Gardiner - had a neat thought, to place Bach's six Motets (BWV 225-230) into the former church in SW1. The building and the motets date from the same decade, the 1720's. Both are beautifully crafted, complex works of art which provide contexts for the act of worship. So far, so natural, then.

An equally clever idea, and perhaps more of a gamble, was to pull back fifty years and to intersperse the Bach works with two of Biber's Mystery sonatas and the Passacaglia for solo violin from the 1670s. That idea also worked successfully, very successfully, not least because Kati Debretzeni, the solo violinist, proved to be such an eloquent and compelling soloist.

A less obvious idea, unclear in its intent, incidentally, was to make the programme straddle a fifty minute "dinner interval." There were also many re-jigging manoeuvres by the participants on stage, in between and during the works, all precisely pre-ordained and militarily organized, but somewhat distracting.

There can be no quibbles about any of the music, however. In the Bach motets I found myself constantly drawn in by the variety, even the audacity of word-setting. I wonder if there is a bolder gesture in setting text anywhere in the Western musical canon, than Bachs setting in Jesu Meine Freude of the four words "Es ist nun nichts..." over three 3/2 bars in clipped minims thus: Es. Ist. Nun./ Nichts. REST. REST/ Nichts REST. REST. Can there ever have been a more emphatic way not just to describe, but actually to create through music the complete void?

Jesu meine Freude was a superb closer for the first half. It took the listener deftly through a journey of many moods. "Lass den Satan wittern" was snarled with open throat, we passed by dragons and their rages, and through chorales to the final comforting vision, where for believers, even their trouble, their "Betrueben" are pure sugar "lauter Zucker."

Bach uses the double chorus to get words spinning round. In Der Geist hilft unser Schwachheit auf the word "heilig" is constantly adored and melodically adorned with flowing quavers. A particularly subtle instance is the setting of "bestaendig" (constantly) in the final chorale, where the sense of durability is reinforced by having the point of arrival on the "st" consonant literally scattered around the chorus.

In the final motet "Singet dem Herrn" (BWV 225), I found myself wondering how many advertising people there were in the audience, because of the extravagant promises made on behalf. All that innocence, that unquenchable belief, not only that things can only ever go right for the believers, but also that they will inevitably go completely wrong for everyone else. Some brand, Christian faith 1720's style.

There were points here where Gardiner's direction seemed to keep the performers on a very tight leash however, the beat in three rather than one in the opening section was perhaps slightly too hectoring. I find myself wanting Gardiner to give the singers the “Gimme more” gesture more often, to trust in the singers, to let their sound bloom more fully.

But such doubts were dispelled in the encore, Ich lasse dich nicht, du segnest mich denn (BWV Anh. 159), which used to be attributed to Bach's uncle Johann Christian was gentle triple time, lilting and comforting.

Kati Debretzeni's performances of Biber's first and tenth Mystery sonatas were finely wrought, and David Miller on theorbo was, as ever, the perfect discreet accompanist. However, the highlight of her performance was the unaccompanied Passacaglia, performed from memory and as a progress through the church from West - behind the audience - to East – on stage.

The piece has at is heart the falling ostinato figure G, F, E-flat, D, marking out an unshakably solid harmonic rhythm, mesmerising through its repetition and allusion, and serving as a basis for all kinds of excursions and expressive descriptive moments.

Perhaps it was the simplicity of Debretzeni's playing, and the power of her sense of line which made her contribution so captivating. But the fact that these performances formed such contrast to the complexity of Bach's devotion made less seem like more, and the spiritual experience of the whole evening more complete.