Ein feste Burg ist unser Gott - Johann Sebastian Bach

Ein feste Burg ist unser Gott, meaning 'A mighty fortress is our God', is a church cantata*. He composed the chorale cantata in Leipzig for Reformation Day, 31 October, first performed between 1727 and 1731. It is based on Martin Luther's chorale "Ein Feste Burg ist unser Gott".

The cantata was written for four vocal soloists (soprano, alto, tenor, bass), a four-part choir, two oboes, two oboe d'amore, oboe da caccia two violins, viola, violoncello and basso continuo.

The work has eight movements:

1. Chorus.
2. Aria and duet (bass and soprano).
3. Recitative and arioso (bass).
4. Aria (soprano).
5. Chorale.
6. Recitative and arioso (tenor).
7. Duetto (alto, tenor).
8. Chorale.

In the second movement, the oboe and soprano perform an embellished version of the chorale while the bass sings an aria.

The fourth movement is a soprano aria* with a continuo ritornello. It is given character by the use of melismas and a "floaty" melody.