Some of the spurious compositions attributed to Johann Sebastian Bach, are not even included in the second appendix of Schmieder's catalogue of Bach's works. That could be because Schmieder considered them not to be compositions by Johann Sebastian Bach, or because they were not known in the time Schmieder compiled his catalogue. Some 30 years ago Reimar Emans compiled a list of possible Bach compositions. Some of these works are now known to be composed by other composers than Bach. Of some however, the composers are still not known and they remain attributed to Bach, however unlikely the authorship pf Bach is.
Emans 129 is one of these pieces of which it seems unlikely that Bach was the comp-oser, even though it is attributed to him in the only manuscript source that is available of this composition.
The choral melody features twice in this composition. First it is played with the right hand in an eleborate version. Then it is played with the feet in plain notes, while the rioght hand plays a lively accompaniment. The left hand is silent in this part of the piece.
The piece feels rather uneven, more like two sketches joined together then a coherent composition. If Bach was the composer he was probably just an early teenager and just begun to learn to compose. Or he just did not have a very good day.
Score available here: http://partitura.org/index.php/johann-sebastian-bach-lobt-gott-ihr-christen-allzugleich-emans-129