I learned and sang Nun danket alle Gott as a bass singer when I was a member of Die Zeitlupe some time in 2006.
The original melody was by Johann Crüger and the words by Martin Rinckart (1618). It was then arranged by Johann Sebastian Bach as a "Trauungschoral" used at weddings and state occasions.
The version we sang is given in Bach Choral Gesänge on page 176.

Lyrics