Is this a cantata? Is this a chorale fantasia movement of a cantata? Is this a concerto? What is this thing?
The answer is: all of the above! By now, it shouldn't surprise us that Bach was not satisfied with simplicity. Here, he combined the chorale fantasia and concerto forms together into this unique first movement of a cantata, achieving some delightful contrasts of orchestral color.
Netherlands Bach Society performs BWV 99: https://www.youtube.com/watch?v=TwmQo97zb6I
Netherlands Bach Society performs BWV 100 (mentioned in this episode): https://www.youtube.com/watch?v=0oS4clt71dU
Come see a (free!) performance of BWV 99 conducted by Alex at his home church of St. John's Lutheran Church, Orange, CA on September 18, 2022: https://www.stjohnsorange.org/event/1222155-2022-09-18-bach-cantata-vespers-concert/