The next choral prelude by Marpurg's hand is the prelude to "Von Gott will ich nicht lassen". Marpurg creates a simple 3 part text, with the choral melody in the upper voice. The left hand plays the accompaniment.
It is fascinating to see that the left hand part is really does not do much more than elaborate the notes of the chord that the bass line indicates. As such it is a nice model for perhaps writing your own choral prelude. You start with a four part harmonisation of a choral melody. Than you leave the notes for the bass voice and the soprano voice the same. And you take the notes for the alto and tenor voice to create a lince that moves in eigth notes between bass and soprano. A further nice trick Marpurg uses here is that he ties almost every fourth note of the middle voice to the next, creating a lot of nice suspensions. It is just the thing this procedure needs, because otherwise the music would have been rather boring. As it is now, it still isn't Marpurg's best composition. But it is a nice model to study.
Score available here: http://partitura.org/index.php/friedrich-wilhelm-marpurg-von-gott-will-ich-nicht-lassen
