Kauffmann's prelude to "Komt her zu mir, Spricht Gottes Sohn" is a very nice example of how to derive a musical piece from a choral melody. The accompaniment of the choral melody is based on a motive derived from the first eight notes of the chorale melody. Kauffmann uses this motive through the entire piece right up to the last bars, gving the pice a strong impetus and unity.
The recording was done with the Hauptwerk software and the sampleset, made by Voxus, of the Müller organ in the Sint Bavokerk, Haarlem (http://www.voxusorgans.com/en/product/haarlem).
Score available here: http://partitura.org/index.php/georg-friedrich-kauffmann-komt-her-zu-mir-spricht-gottes-sohn