This aria formulates two questions with which we imagine Peter is wrestling. The restless jagged dotted rhythms which pervade the string parts give us the impression of Peter’s despair. The words of this aria are heavily based (and probably adapted by Picander) on the first verse of a poem by the Leipzig University librarian and author Christian Weisse (1642-1708) entitled Der weinende Petrus (The Weeping Peter). The violins, violas and cellos of the baroque period were much less powerful instruments than those of today, having a lower bridge and being played with a shorter, lighter bow, resulting in a softer and less penetrating sound. Players would have used vibrato very sparingly, to embellish longer notes as an ornament, rather than as a technique to influence sound quality. The combination of these factors would have made for an easier separation of notes in faster passages of this aria than modern instruments can usually achieve. 

This chorale, which starts as a narrative and turns into a prayer, is harmonised with very modern chord progressions for its time. It gives a sense of unease as the first part of this work comes to a close. Small and subtle appoggiaturas and melismas on words such as weinet (weeps), and büßen (repent) paint the words, and the unexpected chord on the word Böses (evil) must have been quite startling to the congregation. The words, published in Leipzig in 1633, are the tenth stanza of a hymn by Paul Stockman (1602-1636). The melody is by Melchior Vulpius (1566-1615). Bach draws on it again in movements 56 and 60. 

End of Part 1

Part 2

The second part begins as the first part ended, with an affirming chorale sung by the chorus, now representing the faithful believers and followers of Christ. The words for this opening chorale of part two are from a Latin hymn by Michael Weisse (1480-1534). The melody was published in Leipzig in 1531, but the composer is unknown. Again, Bach’s harmony is daring, chromatic and unpredictable.