Bach Cantata BWV 97 is sui generis. It has as its text the first nine verses of the well-known hymn "Innsbruck, ich muss dich lassen," originally a tune by the Renaissance composer Isaac but taken over by Paul Fleming in 1642 to become a mainstay of the Lutheran chorale repertoire. Bach not only sets the nine verses unchanged but treats the whole cantata as a baroque suite; each aria, duet and the opening chorus are identifiable as movements in the suite form. The work opens with a grand French Overture, the traditional beginning of the form. The orchestra of oboes and strings plays the opening characteristic dotted figurations. At the middle section the chorus with the chorale in the sopranos enters. The bravura orchestral writing is reflected in the brilliant roulades in the lower voices of the chorus.
The second verse is set for the bass voice and the continuo as a lively and virtuoso gigue. The third verse of the chorale appears as a secco recitative. The next verse is perhaps the greatest thing in the cantata. This aria for tenor, violin obbligato and continuo, is a broad Allemande portraying the mercy and protection of God. This is the most ambitious and far-reaching of all of Bach's violin obbligati in the cantatas. Although the cantata has an autograph date of 1734, the violin writing is more characteristic of the virtuoso writing of the solo violin partitas and sonatas written in Cöthen in the early 1720's. Here the violin portrays a state of God's grace which the tenor punctuates and comments upon.
The alto recitative is accompanied by strings and leads into the unusual and thorny aria, also with strings. Here the composer clearly wants to confuse the listener rhythmically with the large number of syncopations and ambiguous downbeats. The lovely duet for soprano, bass and continuo is, like virtually every movement in this work, more complicated than it seems. The soprano aria with two oboes is abstract and profound in its structure and content. The cantata ends with an elaborate harmonization for the four-voice choir with independent string parts. This great cantata (and it is one of the very best) may seem more abstract and less emotionally involving than some of the more popular earlier works. It certainly is leading to Bach's last profound period of composition of the German Organ Mass, the Musical Offering and the Art of Fugue. Here, as in those great last works, Bach uses what is probably the greatest technique of any composer to sum up the wisdom of the age. Certainly, at the very least, this cantata is a remarkable compendium of all that can be said about this great chorale.