Il tremore degl'Israeli (Aus tiefer Noth, schrei ich zu Dir)

Two days ago I played BWV 721 on the sample set of the organ of the Martini-kerk in Groningen, with the registration Leo van Doeselaar uses on the real organ in this video (https://www.bachvereniging.nl/en/bwv/bwv-721/).

In the accompanying video and in the description it is stated that a possible model for Bach was one of the Biblical Sonatas composed by his predecessor as Thomas cantor in Leipzig, Johann Kuhnau. Specifically the first biblical sonata that pictures the fight between David and Goliath. To depict the reaction of the Israelis when they first see Goliath, Kuhnau uses the melody of "Aus tiefer Noth, schrei ich zu Dir" set against a same accompaniment of quavers. Kuhnau writes above this part: "il tremore degli Israeli, alla comparsa del gigante, e la lore preghiera fatta a dio" (the tremor of the Israelis, at the appearance of the giant, and their prayer to god)

When you play through Kuhnau's work it is intruiging to note the many similarities with BWV 721. At the same time, it does not reach the same emotional depth as BWV 721. The comparison with Kuhnau's work shows that BWV 721 is the work of a far better composer. So, the authorship of Bach doesn't seem so unlikely to me anymore.

To make a fair comparison, I use the same registration (Holfluit, tremulant) and slider setting as in BWV 721, uploaded here: http://www.contrebombarde.com/concerthall/music/37429