Cantata BWV 9, entitled Es ist das Heil uns kommen her ("Salvation has come to us"), is a choral cantata (Choralkantate) that belongs to the cycle of choral cantatas, although it was composed to fill a gap in that cycle during the later years in Leipzig. It was composed between approximately 1731 and 1735 in Leipzig. The premiere took place on July 1, 1731 (or possibly July 20, 1732 according to some sources, but most agree on 1731 or around 1731-1732) for the sixth Sunday after Trinity. The readings for the day included the Gospel of Matthew 5:20-26 (part of the Sermon on the Mount, on justice that surpasses that of the Pharisees and reconciliation), which is thematically related to salvation by grace and not by works of the law, the central theme of the hymn.
The work is based on the Lutheran hymn Es ist das Heil uns kommen her by Paul Speratus (published in 1524 in the Achtliederbuch, one of the first Protestant hymnals). The hymn consists of 14 stanzas (although Bach mainly uses the first and last ones). It is a key hymn of the Reformation, emphasizing salvation by faith and divine grace, not by one's own merits. Bach used the text of the hymn literally in the outer movements (stanza 1 in the opening chorus and stanza 12 or final stanza in the concluding chorale). An unknown librettist paraphrased the middle stanzas for the recitatives and arias, adapting them to the theological message of the day.
The cantata consists of seven movements, framed by the opening and closing chorales, typical of the choral cantata format:
- Chorus – Es ist das Heil uns kommen her (stanza 1 of the hymn, choral fantasy with cantus firmus in the soprano).
- Recitative (bass).
- Aria (tenor).
- Recitative (alto).
- Aria (bass).
- Recitative (tenor).
- Choral – Final verse of the hymn, harmonized for four voices.
The structure is simpler and more austere than other choral cantatas from the main cycle of 1724–1725, with fewer movements and a more direct focus on the doctrinal message.
The instrumentation is relatively modest, with the flute and oboe providing expressive obbligati in the arias, and a contemplative and devotional character in keeping with the theme of salvation by grace.