||Warum betrübst du dich, mein Herz?
Grove Music lists this as simply for voices and continuo. The Engelke edition has a separate "basso instrumento (Fagotto o Trombone)" line to the continuo line, and this in turn is separate from the staves marked "(orgel)", but the bass instrument line is almost identical to the continuo line except for about 10 bars that are more florid than the continuo line. Given the strength of the organ sound, it is difficult to see why an extra continuo bass instrument would be needed. Also, the subtitle is "à 4", and since the continuo players are considered one, the only way it totals four is if the "basso instrumento" line is counted as part of the continuo. Therefore, the "Fagotto o Trombone" is being treated as an editorial suggestion that would match the stronger sound of the organ.