This cantata was originally written for the inauguration of the Leipzig town council in 1723. It was then used on the Twelfth Sunday after Trinity, which was the Sunday of the week in which the council was held that year. Some years later, Bach revised the cantata for the same purposes (inauguration and the Sunday of the week when the council met); at this later date, the recitative texts were changed in order to fit the Sunday Gospel better, and a different chorale was substituted at the end.
The work is scored for three trumpets, timpani, three oboes, bassoon, strings, continuo, SATB choir, and SATB soloists. Trumpets and timpani are reserved for the first and final movements; in the first, they add significantly to the festive character of the piece. The in the last, while the other instruments double the choral voices in the final chorale of the cantata, the trumpets and timpani are rhythmically similar, yet independent of the voices, adding occasional flourishes and ornamentation to create a more celebratory air than we normally see in one of these final chorale settings. In the first movement, the trumpets clearly have the lead role in the instrumental introduction; in fact, the trumpets introduce the first melodic idea of the movement, essentially unfettered by the string section, which traditionally dominates.
No one knows the author of the text, though there is some speculation that it might have been Christian Weiss, Sr. (W. Murray Young, The Cantatas of J.S. Bach: An Analytical Guide). Only the text of the first movement has biblical routes, coming from Psalm 103.
The first movement uses several fugues, each of which is introduced independently, and then combined in the end. The first fugue uses a theme which is related to the initial trumpet melody.
First fugue subject:
The similarity is pretty clear, though the most obvious connection is in the undulating sixteenth notes leading to a trill, marked in red in both examples.
The fugue is a bit unusual, in that the subject is initially heard in the altos (m. 24), followed closely by tenors (m. 25); they finish together at the downbeat of measure 29, at which point the sopranos, and then basses (m. 30) take their turns with the fugal subject. Normally, we would hear the subject emerge first in one voice, then a second, then a third, then a fourth, with each of the four voices continuing to build a four-part texture. Bach reserves that sound for measures 36-46, though here the independence of the four lines normally seen in a fugal texture is significantly reduced. As you can see below (which shows only a portion of this passage), the four parts are rather similar rhythmically, and textually in unison.
The next fugue is more traditional, and similar to the first fugal subject. Here, the sopranos introduce the subject, moving downward through the texture to the altos, then tenors, then basses, beginning in m. 46:
Next, after a brief instrumental interlude, the basses take this same fugal subject and reintroduce it (beginning in m. 64), after which it moves upward through the vocal ranges, BTAS. A totally new fugue subject begins then at m. 78, in the tenors, for the first time introducing a new text.
Beginning at m. 95, these two main fugal subjects are combined for the rest of the vocal material. Overall, the movement uses a dal segno design, where the bright instrumental opening return with “magnificent impact” (Young) after the two fugues are combined. No other movement in Cantata 69 has the complexity, weight, or magnificence of this opening movement, which serves as the focus.
Two recitatives precede the two arias (movements 3 and 5). Bach uses the lower of the female and male voices, respectively, for the two arias, leaving the recitatives to the soprano and tenor. The alto aria is a lilting 9/8 da capo aria, which feels a bit like a lullaby. That would seem to be counter to the text, which demands the soul to wake. Perhaps the compound meter and G major tonality are, instead, a pastoral reference, which portrays Christ as the “Good Shepherd”. By contrast, the bass aria is more pleading, more prayerful, set apart from all other movements of the cantata by its minor tonality (B minor), enhanced by the darker timbre of the oboe d’amore.