Bach performed his number 7 on the day before BWV 135. It was celebrating the Feast of St. John the Baptist, so the text is Luthers retelling of the baptism of Christ, by St. John. BWV 135 is planned for the third Sunday after Trinity, which in that year fell one day later. Never mix a lunar calendar with a solar calendar. It leads to terrible confusion.
This whole series from Helmuth Rilling is actually odd for me. Most Early Music that I have, either on vinyl or cd, was performed on period instruments, in what has been called historically informed style. This one is not, although it does pay close attention to its sources.
The way this series treated that source material was for me the reason I bought this. In one of the first pieces I wrote about this series I showed the inlay that accompanies these records. It goes into detail about the the piece. It describes the sources of the text and the text itself, but also has some music notation examples. It was food for my inner nerd.