This is a transcription of the last forty-five bars of the final chorus of Cantata 131 (1707), whose opening and closing movements are, unusually, a prelude and fugue, the latter a permutation fugue of three subjects (Example 1).This conforms to the tradition of choral permutation fugues (Krüger1970 p. 11), as in other early works: Cantata 196, the Capriccio in B♭ major. Perhaps the model is Reinken'ssonatas and through them ultimately Frescobaldi's Fiori musicali. Unlike the Passacaglia fugue, BWV 131a has nointerludes, and its many tonic cadences are typical of such fugues. After Frescobaldi, one line in a permutation fugue was often chromatic, with influentialexamples in Kuhnau's Clavierübung II (Leipzig, 1692) and also Pachelbel's Magnificat primi toni, v. 19 (1701–5?), which has achromatic fourth subject and countersubject much like b. 3 of Example 1.

J. S. Bach is usually thought not to be the arranger (Spitta I p. 451), and as with BWV 539, details make it unlikely to be authentic: the sources (many, but from a common route), certain unidiomatic moments, omission or alteration offugal parts, and little in common with the authentic early fugues BWV 531, 549a. Lines impossible for two hands are omitted and the basssimplified. The succinct ending, though also vocal, need not be Bach's (as Bartels 2001 suggests), but could be the work of an arranger such as Kittel. Thecantata's ending was surely the original, i.e. with a gradual buildup from two to five parts.