As I publish these pieces more or less in the order as they appear in manuscript Mus. ms. 40037, the next one in line is Zachow's prelude to "Wo Gott der Herr nicht bei uns hält". No intricate counterpoint this time. Zachow writes the choral melody in the upper voice, and provides an accompaniment in the other two voices, that is mainly based on a simple harmonisation of the choral melody. It is infact a nice model to practise improvising in the same style.
The recording was done with the Hauptwerk software and the sampleset, made by Sonus Paradisi, of the Hinsz organ in the Reformed church in the Midwolda (https://www.sonusparadisi.cz/en/organs/netherlands/midwolda-surround-sample-set.html).
Score available here: http://partitura.org/index.php/friedrich-wilhelm-zachow-wo-gott-der-herr-nicht-bei-uns-halt-lv-45
https://youtu.be/gBDTaPxCgro