"I, wretched man, a servant to sin" in G minor, BWV 55

The prescribed readings for the Sunday were from the Epistle to the Philippians, thanks and prayer for the congregation in Philippi (Philippians 1:3–11), and from the Gospel of Matthew, the parable of the unforgiving servant (Matthew 18:23–35). Christoph Birkmann, the poet of the cantata text stressed the opposites of the gospel, God's justice versus unjust men, in the words of the first aria "Er ist gerecht, ich ungerecht" ("He is just, unjust am I"). In the first two movements the singer reflects his sinful condition, in the following two he asks God for mercy, beginning both with Erbarme dich ("Have mercy"). The following closing chorale is verse 6 of Johann Rist "Werde munter, mein Gemüte" (1642). Bach used the same verse later in his St Matthew Passion, again following Erbarme dich, the aria of Peter, regretting his denial of Jesus.