rather marginal: the Lord's comforting (movement 3) and destruction of the enemies (movement 5) refer to the epistle, while the theme of the hymn, the joy about a repenting sinner, connects to the gospel. The unknown librettist retained the first and last stanza unchanged. He paraphrased the other four stanzas to four movements, for alternating recitatives and arias. Music Structure and scoring Bach structured the cantata in six movements. The first and last are set for choir as a chorale fantasia and a closing chorale. They frame alternating recitatives and arias with the text arranged by the librettist. Bach scored the work for three vocal soloists (alto (A), tenor (T) and bass (B)), a four-part choir, and a Baroque instrumental ensemble: cornett (Ct) to reinforce the soprano chorale tune in the last movement, trombone (Tb) to reinforce the bass chorale tune in the first movement, two oboes (Ob), two violins (Vl), viola (Va), and basso continuo (Bc). The duration of the cantata has been stated as 17 minutes. In the following table of the movements, the scoring follows the Neue Bach-Ausgabe. The keys and time signatures are taken from the book by Bach scholar Alfred Dürr, using the symbols for common time (4/4) and alla breve (2/2). The instruments are shown separately for winds and strings, while the continuo, playing throughout, is not shown. Structure The opening chorus is a chorale fantasia as in the previous chorale cantatas. Bach had started the first one of his second cycle with the cantus firmus of the chorale tune in the soprano, in this fourth work the bass has the honour. According to the Bach scholar Christoph Wolff, the first four cantatas of the cycle form a group, distinctively different in their chorale fantasias. After a French Overture (), a motet () and an Italian concerto (), the movement is an "extraordinary filigree of vocal and instrumental counterpoint" of the chorale melody. All parts, even the instruments, take part in the polyphonic setting of the tune. Bach used the melody, originally a love song, later for the first chorale of his Christmas Oratorio, "", and several times in his St Matthew Passion, most prominently "". All eight lines of the text are first treated instrumentally, then vocally. The instrumental anticipation is a trio without continuo of oboe I and II against the strings, which play in unison the cantus firmus. In stark contrast