Like so many composers of his day, J.S. Bach was not at all afraid to reuse good musical material. Sometimes he plundered the same source more than once; this is the case with the music from which he drew the Cantata No. 169, Gott soll allein mein Herz haben, BWV 169, of 1726 -- a now-lost oboe (or possibly viola) concerto. It is the source not only for two of the numbers in BWV 169 but also for the Harpsichord Concerto in E major, BWV 1053 from about ten years later. Gott soll allein mein Herz haben was composed for the eighteenth Sunday after Trinity (which fell on October 20 in 1726) and is a setting of an anonymous text.
Bach uses a medium-sized ensemble in BWV 169: solo alto, two oboes (really oboes d'amore), oboe da caccia (or taille), strings, organ obbligato, and alto solo. The opening sinfonia and No. 5, the aria "Stirb in mir" ("Die in me"), are the two portions of music extracted from the lost oboe/viola concerto; each is a whole step lower than its counterpart in the later Harpsichord Concerto (E and C sharp minor in the harpsichord work are D and B minor, respectively, in the cantata). In the sinfonia, the organ obbligato is honored with the task of reproducing the original solo part. In "Stirb in mir," things are not quite so simple: the organ and the alto soloist offer, simultaneously, slightly different versions of the original solo line -- sometimes their two versions line up note-by-note, but sometimes, usually so that the alto might better carry the text, they diverge and become counterpoints to one another. Bach sets a new text to an old melody, that of the Lutheran hymn "Nun bitten wir den Heiligen Geist," in the final chorale, "Du süsse Liebe."