Marpurg's prelude to "Jsu meine Freude" is one of the most beautiful pieces of music Marpurg wrote. Perhaps it is even the most beautiful one.
The introduction of this prelude is full of longing and tender singing phrases. It is almost a pity when the introduction comes to an end and the choral melody starts. Luckily, this particular choral melody is a beautiful one as well and the music continues with the same emotional intensity.
The only thing I regret is that Marpurg did not write a coda in which he retakes the material of the introduction. That would had made it a really great piece. Though, as it is now, there is more then enough to enjoy.
The recording was done with the Hauptwerk software and the sampleset, made by Sonus Paradisi, of the Schnittger organ in the St. Martini-kerk, Groningen (https://www.sonusparadisi.cz/en/organs/netherlands/groningen-st-martini.html).
Score available here: http://partitura.org/index.php/friedrich-wilhelm-marpurg-jesu-meine-freude