This piece is based on material from Bach's motet Jesu Meine Freude, BWV 227 Number VIII, So aber Christus in euch ist.
The text of this movement is Romans 8:10-- "If now Christ Jesus lives in you, although the body is dead because of sin, the Spirit is life because of righteousness."
In the motet, this piece appears in C major, voiced for alto, tenor, and bass. It ends with an E major chord to set up the chorale fantasy that follows. This means that it would be almost useless to present this as a straight transcription as the ending would be quite unsettling to the listener. The "fix" was to remove the final phrase and splice a modification of the opening phrases in its place returning the piece to its starting key. This version is written in Eb major to accommodate the vocal range of the three parts.
IF NOW CHRIST JESUS LIVES IN YOU, by J. S. Bach, arranged by Tom Kirkland for unaccompanied SAB choir, comes in a pdf file of 499K, a six-page score and a license page, seven pages in all. Performance time should be about 2:15.