The most religious music in the classical repertoire is, in my opinion, the solo keyboard output of Johann Sebastian Bach. The line between secular and devotional music blurs significantly in Bach, reminding of how that most devout of all composers, Anton Bruckner, never began a day of composition without first playing through a few of the master’s preludes and fugues.

So listening to Bach on a modern piano within the confines of a church seems particularly apropos. On Monday afternoon at St. Paul’s Chapel, the fine Israeli soloist Ofra Yitzhaki offered an hour of what another contemplative organist-composer, Olivier Messiaen, called “Illuminations of the Beyond.”

I arrived early enough to listen to Ms. Yitzhaki’s warm-up and then stayed for a very moving service. St. Paul’s is the house of worship just in front of the World Trade Center site.They still ring the fire bell once for each of the firefighters who died on September 11, 2001; the sound triggered deep emotions that set the stage for old Bach’s intricate glorification of God.

Ms. Yitzhaki fashioned an intelligent program. She began with two pairings of inventions and sinfonias (sometimes known as two- and threepart inventions), arranged by key rather than by degree of difficulty. Bach published them in three separate editions, the first two for pedagogical facility, the third more sophisticatedly structured musically. It was this later edition that Ms. Yitzhaki chose, drawing an instant parallel to the preludes and fugues to come.

The acoustics at St. Paul’s are very different from those at Trinity Church down the street. No cathedral ceiling, no echo – just a raised platform in a medium-size room. Ms. Yitzhaki employed a baby grand that was just right in volume and especially bright in timbre.

Ms. Yitzhaki is known in New York primarily as an exponent of cuttingedge contemporary music at such events as the Museum of Modern Art’s Summergarden and Lincoln Center’s Focus Festival. She is applying for her doctorate at Juilliard, where she previously studied with Jerome Lowenthal and Jacob Lateiner. Technically, she is exemplary, but I had a difficult time looking at her while she played. She holds her hands very high, with the fingers of the left often perpendicular to the keys. It is amazing that she can play so fluidly from this position. Of course, if we went strictly by the book, then we could never have enjoyed Vladimir Horowitz or Glenn Gould.

Ms.Yitzhaki’s spirited attacks served her well in the Partita No. 6, with its distinctive opening measures in Bach’s tragic key of E minor. Her renditions of the inventions and sinfonias in A major and F minor were models of digital coordination. Her trills were steely and remarkably precise. Ms. Yitzhaki is a master of a keyboardist’s trick wherein she slows down almost imperceptibly at various times in order to concentrate on pinpoint accuracy. This is so much better than the devil-may-care attitude of others who sacrifice precision for the sake of metronomic uniformity. Artur Rubinstein, for instance, used to simply make up passages to stay on beat.

This pianist exudes confidence and an infectious sense of pure enjoyment: She seems naturally delighted to play Bach. While staying within the strictures of the Baroque, she demonstrated her profound phrasing abilities. For example, the English Suite in E minor begins with a solemn and thoughtful prelude that she emphasized in bas relief by creating a significant demarcation from the dances to come, a grouping that she then took at a brisk pace without pause. It was almost as if the prelude were a different piece of music from the kinetic material that followed.

After offering the initial pairings of pieces, Ms. Yitzhaki traversed two of the mighty preludes and fugues, the Csharp major, BWV 872, and the C-sharp minor, BWV 873. The first prelude was a granitic statement, though the quickstep of the fugue led Ms. Yitzhaki off the rails. She made a nice recovery in the second duo and finished with a flourish. This playing felt utterly genuine, offering strong support for the theory of critic Hermann Kretschmar that Bach’s small keyboard essays were both the wellspring and the cornerstone of German music.