The beautiful passage about the servant of two masters and the lilies of the field is the Gospel for the 15th Sunday after Trinity. Its feeling of warmth and abundance permeates the gorgeous opening chorus of Cantata BWV 99. This chorus overlays the wonderful chorale tune ”Was Gott tut, das ist wohlgetan” upon a concerto movement for flute, oboe d'amore and strings. The lilting tune sets the tone for the whole chorus. The whole movement has a marvelous sense of generosity and openness. Just the first violin line of the first cadence illustrates this. The actual chorale is a big arching tune, quite different than the stepwise motion that we are used to in most of the chorales. There are too many felicities of detail to enumerate here, but one should notice the structure of the opening. Strings play an opening tutti for 16 bars. The oboe d'amore enters in the seventeenth bar with the theme, the flute playing a bubbling obbligato. One would expect the chorale to enter either with the concerto soloists or on, perhaps the second phrase. Instead the first entrance is put on the cadence of the first solo concerto phrase, where one least expects it. The actual treatment of the chorale is significant. The soprano in long notes always begins alone with the bottom three voices imitating at a respectful distance. Certainly Bach hears the soprano here as the voice of God, leading the way for the poor mortal altos, tenors and basses. The final tutti, instead of being a repetition of the opening, is even more extravagant in its sheer beauty.
Most of the cantatas that we have been dealing with have begun with a conflict and ended up, some of them rather near the end, with a resolution. Our cantata here begins with great faith and confidence. Both of the subsequent concerted pieces, an aria and a duet have darker sides, although they are composed with the lightest of touches. The tenor aria with flute (#3) has passing chromatic passages and some quite daring harmony. It retains, however, a mood of quiet confidence. Notice how all of the vocal lines are literally turned upside down in the B section, as if one were seeing the situation from God's point of view.
As marvelous as this aria is, it is the soprano-alto duet with flute and oboe d'amore obbligati that brings the cantata to its climax. Again the first thing that one notices is the lightness of touch. The opening continuo line moves with the quietest of steps. The flute and oboe d'amore play a haunting little theme in canon with the most delicate of chromatics. Although the text sung by the singers is about the “Kreuzes Bitterkeiten,” it is clear that this is but a dim memory. The whole tone is of an elevated state of grace. How different are the long melismas of the two singers than the rather dogged ones three weeks earlier in the soprano-alto duet of Cantata BWV 113. Here, they have a kind of shimmering quality that illuminates the text like a lantern in the night. One is surprised that the duet is not a da capo until it becomes clear that the final chorale is the resolution, and that its first line of text is almost identical with the last line of text in the a section of the duet. Surely this is one of the most perfect cantatas in the whole literature.