Johann Sebastian Bach composed the church cantata Was Gott tut, das ist wohlgetan (What God does is well done),[1] BWV 99, in Leipzig for the 15th Sunday after Trinity and first performed it on 17 September 1724.

The chorale cantata is based on the hymn "Was Gott tut, das ist wohlgetan" by Samuel Rodigast (1674).

The cantata is scored for four vocal soloists, a four-part choir, and a Baroque instrumental ensemble of flauto traverso, oboe d'amore, strings and basso continuo, with a horn doubling the soprano in the outer movements.

[2] The cantata text is based on the chorale "Was Gott tut, das ist wohlgetan" by Samuel Rodigast,[2][5] which is generally related to the Gospel.

[2] Bach structured the cantata in six movements and scored it for four vocal soloists (soprano (S), alto (A), tenor (T) and bass (B)), a four-part choir, and a Baroque instrumental ensemble of a horn (Co) to reinforce the chorale tune in the outer movements, flauto traverso (Ft), oboe d'amore (Oa), two violins (Vl), viola (Va), violone (Vo) and basso continuo.

[8] After 16 measures, a concertino of flute, oboe d'amore and violin begins, with the oboe playing the theme introduced by the strings and the flute playing a virtuoso counterpoint.Three measures later, the voices enter, with the cantus firmus in the soprano, doubled by the horn.

"[6] The first secco recitative is sung by the bass, "Sein Wort der Wahrheit stehet fest und wird mich nicht betrügen" (His word of truth stands fast and will not betray me).

[4] The second recitative, for alto, "Nun, der von Ewigkeit geschloß'ne Bund bleibt meines Glaubens Grund" (Now, the covenant sealed from eternity shall remain the foundation of my faith),[1] is similar to the first, ending on the last word "erscheinet", or "appeareth", as in "when God's true loyal will appeareth".

[10][11] Choirs singing with one voice per part (OVPP) and ensembles playing period instruments in historically informed performances are shown with a green background.