At the beginning of his tenure as court composer in Weimar, Bach set several of the texts of J.C. Lehms. The Lehms texts are the most luridly bloody and preachy of all the Bach texts. They also have a raw power that suits Bach’s in-your-face style of that period. The opening aria of Cantata 54 is one of the most astonishing things in all of Bach. Sin is portrayed as a gorgeous, irresistible thing. One is reminded of the Andrew Marvel poems that refer to the jewel-like blood on the back of Jesus. The aria begins with a grinding and shocking dissonance in the orchestra. Gorgeous, lapping phrases build up like layers of velvet on this dissonant bass. The expressive voice part is like a rich, deep nap on the many levels of gorgeous chromatic harmony. Bach wants us, in this lengthy and incredibly expressive aria, to feel the push and temptation of sin. The lengthy recitative that follows clarifies his point of view. The fugal last aria is spikier but no less astonishingly chromatic. While this cantata is not very well known, it is a remarkable missing link in the Bach oeuvre and essential to our complete understanding of this composer.