One learns every day. Both these cantatas were written for a SATB choir. That is a choir with four voices, consisting of soprano, alt, tenor and bass. Yay for wikipedia.
Both of these were also for Christmas, so I’m writing and listening on the wrong date. It cannot be helped. Interestingly, BWV 63 is a lot older, and was written by Bach in or around 1713. The other is part of his cycle of Cantatas in Leipzig in 1724.
Looking at wikipedia about this particular cantata, I noted that the recordings of cantata cycles seem to go according to fashion. In the fifties they were popular, then they were again done in the seventies and early eighties. By 1982 another break settled in, only to started again in 2000. There are significant gaps in between. And especially cantatas were popular in the seventies: there were three integral series at the same time.