Präludium und Fuge B-Dur "Ermuntre Dich mein schwacher Geist"

Or as in JSB's Christmas Oratorio - "Brich an o schöne Morgenlicht". A beautiful chorale that is literally "dominant" in its melodic line ;-)
The prelude was originally intended as a chorale arrangement, but as it progressed the voices moved further and further away from the chorale theme into a polyphonic fabric .....
It is followed by a complex 4-part fugue, which once again sets off on a journey through the circle of fifths.
A simple chorale movement ends this once again very expansive composition.
We hear the small but very beautiful Mascioni organ in Azzio.