Bach Christmas: voice to a part cantata?

Whilst decorating, we moved house over Christmas, I was enjoying the Bach Christmas on Radio 3. In particular a [single] voice to a part cantata caught my ear. Didn't get chance to write it down and now can't find it on R3 website. I know there are hundreds of cantatas [I listened to a lot of Radio 3 this Christmas] but can anyone identify any voice to a part cantatas?
best
stephenjohn