The third and last of the three spurious chorale preludes to the Christmas choral "Vom Himmel hoch da komm ich her" is a bicinium. The right hand plays the choral melody and the left hand plays a one part accompaniment. It is a well constructed piece with ingeniously constructued motivic play in the left hand part. That in itself lends credibility to the supposition of J.S. Bach being the composer of this work. But it is hardly conclusive proof. Johann Bernhard Bach for example is the composer of equally well constructed bicinia and he might be the composer of this one as well.
The authorship will remain an enigma.
The recording was done with the Hauptwerk software and the sampleset, made by Voxus, of the Müller organ in the Sint Bavokerk, Haarlem (http://www.voxusorgans.com/en/product/haarlem).