The cantata is based on the seven stanzas of the hymn Wer nur den lieben Gott läßt waltenbyGeorg Neumark, published in 1657. The first and last stanza of the chorale were used for the outer movements of the cantata, while an unknown librettist paraphrased the inner stanzas of the hymn into the text for the five other movements. The first movement, a chorale fantasia, is followed by a succession of arias alternating with recitatives, leading to a four-part closing chorale and featuring a duet in the centre.
Bach composed the chorale cantata in 1724 as part of his second annual cycle for the Fifth Sunday after Trinity. Only continuo parts of the first four movements survived of the first performance. The manuscripts of the complete music date from another performance around 1732/1733, therefore it is unknown if the cantata had the same structure from the beginning.[2]
The prescribed readings for the Sunday were from the First Epistle of Peter, "Sanctify the Lord God in your hearts" (1 Peter 3:8–15), and from the Gospel of Luke, Peter's great catch of fish (Luke 5:1–11. The cantata text is based on the chorale in seven stanzas of Georg Neumark, written in 1641 and published in 1657 in Fortgepflantzter Musikalisch-Poetischer Lustwald.[3] The chorale is connected in general to the prescribed readings. Specific reference to the Gospel appears in the recitative addition of movement 5. The words of the chorale remain unchanged in movements 1, 4 and 7 in a symmetric arrangement. The changes in the other movements are the work of an unknown poet. In movements 2 and 5 he kept the original words but expanded them by recitatives, in movements 3 and 6 he transformed the ideas of the chorale to arias.[2]
In the central duet violins and violas play the melody of the chorale.[5] Bach later arranged this movement for organ as one of the Schübler Chorales, BWV 647.[6]
The opening chorus is a concerto of three elements: the orchestra, dominated by the two oboes, playing an introduction and ritornellos, the cantus firmus in the soprano, and the other voices which start each of the three sections and keep singing on the long final notes of the cantus firmus, soprano and alto opening the first section, tenor and bass the second, all four voices the last section.
Movements 2 and 5 are composed in the same fashion, alternating the slightly ornamented lines of the chorale with recitative.
In the first aria Bach uses a motive which turns the beginning of the chorale melody to major, to express trust in God. The cantata concludes with a four-part setting of the chorale.[2][7]
