I wrote this for the King James Trust 2011 composition competition. I had intended to enter both categories but failed to get my act together in time, so this was thrown together rather hastily. However, I do like it for what it is: short, sweet, simple. It should work well with either organ or piano. If you had a flute or another instrument, it would lend itself to a descant based on the keyboard part or, for a more advanced player, a skilled music director could write a more complex descant.
The MIDI robots play this just a bit too slowly, I think, but there is a MIDI file here and a PDF file here. As usual I've used a Creative Commons license.