The fifth line in the first verse is "As weary souls, with sin oppressed," sung to this musical phrase (from the tune "Du Lebensbrot, Herr Jesu Christ"):
The phrase generally descends, and it includes the lowest note in the entire tune (a B). Both of these features musically represent the qualities mentioned in the text. It's as if the tune itself sinks because of weariness and being oppressed by sin.
