German dative can be peculiar. Dir is to thee but to express the thought in the poem in our idiom, it must be turned over. In our grammar, we tend to leave out much that Germans think (or used to think) necessary.
Bach wrote some interesting secular cantatas, and in them used some words and dialect that were no longer in general use but which persisted among the peasants and country people. Like many great composers, he has an ear for folk.
Toadfrog, I agree with you.