If my Anglican lectionary is to be believed, today is the Feast of the Archangel Gabriel. I’m not sure what to do with that in a Lenten context, but I see that one of the Psalms for the daily Mass is Psalm 46, and that, my friends, is the Psalm which Luther turned into the hymn which English speakers know as ‘A Mighty Fortress is Our God’.
Bingo. It’s well known that where Luther goes, Bach is sure to follow, and sure enough, Bach has apparently gotten hold of Luther’s hymn and has cantata’ed the living daylights out of it. It’s a lot of fun, and if you are having trouble finding the hymn tune in all the enthusiastic fugueing of the first movement, the soprano in the second movement should give you a better idea of how it goes. Or go to 14:47, which is where the chorale starts.
This is nearly half an hour of music in total, by the way, so you might want to just listen to one or two movements, or keep it for the end of the day when you have some time to enjoy it properly.