In this year's Leaving Certificate for students in Ireland, the music exam consists of examples from Tchaikovsky's Romeo and Juliet, Irish composer Gerald Berry's Piano Quartet, and Queen's Bohemian Rhapsody. Also in the exam is this chorale cantata composed in 1724 in Leipzig for a church service in which the biblical story of Jesus healing the lepers was read. 

The hymn Bach based this work on was flexible enough for a dramatic span of affectations across the seven parts of the cantata. In this episode we will look at moments in the duet, and also speak to the other parts, through the final chorale. 

The relative simplicity of the final chorale is defied by its several complexities. Its text is prayer-like, much like the other movements, with its first line reminiscent of the familiar saying "Lord, I believe; help me in my unbelief (weakness)." Even in relatively simple harmonization, the text is full of vivid emotion. Bach enjoys a chance for a militaristic trill near "Streit" (battle) and a Picardy third on the last note of hopefulness ("sweet eternity"). 

In the preceding recitatives and arias, the text painting is even more on-the-nose, as is the case with Bach. But while other cantatas have a single affectation, this one is always changing. 

BWV 78 as performed by the Netherlands Bach Society