A few weeks ago, a colleague of mine gave me a short history on Gregorian chant. I do not know the author's name. This tract contains some useful information (even if there are no proper citations), as well as some outdated information, such as the claim that St. Gregory the Great reorganized the Antiphonarium. Nothing in this document, however, is offensive.
Until the reader gets to this statement:
The religious works of Bach, Mozart, and Beethoven, although of great musical worth, are nevertheless antithetical to the religious spirit of Gregorian chant.
Now, I do not wish to engage in a discussion about Mozart or Beethoven; that is off the table, and any comments approaching the subject will be deleted, if for no other reason than to keep us on topic. But Bach? Really? Does this author have any acquaintance whatsoever with a large sampling of his work? Surely Bach wrote some music that might be considered to be "antithetical to the religious spirit of Gregorian chant," but to include his work in the blanket statement above is ridiculous.
Consider, first and foremost, the great B Minor Mass, specifically the beginning of the Credo, which employs one of the oldest recorded melodies in all of Western music. Bach takes this chant theme and develops one of his masterful fugues out of it. (This particular fugue happens to be a seven voice ricercare fugue with 23 entrances, according to my notes in my score.) This whole movement is therefore filled with a Gregorian, not to mention a Palestrinian, spirit.
Don't forget, either about the many chorale melodies which Bach employed over the course of his career which were based on chant themes. (Nun komm der Heiden Heiland, Christ ist erstanden, and Christ lag in Todesbanden are the ones that come immediately to mind.) Let's stick with Nun komm der Heiden Heiland. (Sorry, no score links for this one.) In the Leipzigoriginalhandschrift, a collection of eighteen organ chorale settings, Bach has set several versions of this melody. One is an introspective, meditative coloratura which is a study not only in beautiful melody but also in imitative techniques. How could this fail to be considered in line with the Gregorian spirit and the spirit of the Golden Age of polyphony? Another setting, with the cantus firmus of Nun komm in the pedal, employs a vigorous, dance-like four voice fugue in the manuals. Does Gregorian chant not dance sometimes? This fugue also relates quite organically to the modal cantus firmus.
There are more examples (I suspect I could find some good instances in the chorale partitas), but I am in a hurry (off to the opera!) and haven't the time presently to explore this any more deeply; perhaps at a later time I'll follow up, should any of you be interested.
We traditional musicians need to be careful about what we eschew, lest we end up disqualifying everything less than five hundred years old that wasn't written by Fr. Carlo Rossini or the Cecilians. Then we simply have a recipe for mediocrity when it comes to post-Renaissance music. Sacredness is important, but no amount of it can cure mediocrity.