Cantata BWV 186 is one of the most seldom heard of all the cantatas. It has a curious history. It first was written in Weimar for the third Sunday of Advent. When Bach moved to Leipzig, which has no concerted music in the last three Sundays of Advent, he added five movements to make it suitable for the 7th Sunday after Trinity.
It begins with a striking chorus, not unlike the Schütz “Saul” in harmony. The word “Ärgre,” which means “to vex,” is the operative affect. After a recitative, the bass sings a rolling and energetic aria with continuo. In the Weimar version, the tenor aria which follows has viola obbligato. The Leipzig version writes the line up an octave and sets it for violins and oboe. It strikes me as one of Bach’s few mistakes. The viola version is dusky and atmospheric and altogether more suited to the text. The concerted setting of the great chorale “Es is das Heil” is unusual, ambiguous and altogether different than any of his other versions of the tune. The second half begins with a large accompanied recitative for bass. The soprano aria is one of his great arias, remarkable for both its chromatic and tortured harmony and expressive intensity. The final duet with soprano and alto is entirely different, a sophisticated and energetic jig which builds up an enormous head of steam. The same odd setting of “Es ist das Heil” closes this ambitious and impressive cantata.