I'm publishing this piece far in advance so that everyone who is interested in playing it in time for Lent, could have plenty of time to prepare. Of course, if you like it, I think there is no harm in playing it on some other occasion.
The piece is not difficult to master. It is constructed in a way that the ostinato chordal section moving in parallel 4/2 chords (7th chords in the 3rd inversion) alternates with the solo melody of Gregorian chant.
Enjoy it and if you like it, share it with other organists.