Erforsche mich, Gott, und erfahre mein Herz (Examine
me, God, and discover my heart), BWV 136, is a church
cantata by Johann Sebastian Bach. He composed it in
1723 in Leipzig for the eighth Sunday after Trinity and
first performed it on 18 July 1723.
Bach composed the cantata in his first year in Leipzig
for the eighth Sunday after Trinity, in his position as
Thomaskantor. The prescribed readings for the Sunday
are from the Epistle to the Romans, "For as many as are
led by the Spirit of God, they are the sons of God"
(Romans 8:12–17), and from the Gospel of Matthew, the
warning of false prophets from the Sermon on the Mount
(Matthew 7:15–23). The sources show, however, that only
the middle section of movement 3 and the chorale were
composed then with certainty. The other parts may rely
on a former unknown secular or church cantata. The
opening chorus is based on Psalms 139:29. The poet of
the recitatives and arias, which are closely connected
to the Sunday's gospel, is unknown. The chorale is
verse 9 of Johann Heermann's "Wo soll ich fliehen hin"
(1630) on the melody of "Auf meinen lieben Gott", which
Bach used again in 1724 as the base for his chorale
cantata Wo soll ich fliehen hin, BWV 5.
The opening chorus is mainly in two parts (A and A'),
with choral fugues on the same themes, both presenting
the complete text. An extended instrumental ritornello,
dominated by the horn, is heard before, between and
after the choral sections. The first fugue is preceded
by a choral Devise (statement). Throughout the movement
the two oboes never play independently but double the
violins in the ritornelli and the soprano in the vocal
sections. Bach used this movement later as the base for
the "Cum Sancto Spiritu" of his Missa in A major.
The two recitatives are mostly secco, only the last
measures of movement 4 tend to an arioso. The aria is
accompanied by the oboe d'amore, the middle section
(certainly composed in 1723) is marked presto. The two
violins in unison accompany the duet, while the voices
sing sometimes in imitation, sometimes in homophony, in
the style of duets Bach wrote in Köthen.
The chorale is expanded to five parts by an independent
violin, similar to the chorale of Erschallet, ihr
Lieder, erklinget, ihr Saiten! BWV 172.
Although the cantata was scored for three soloists
(alto, tenor and bass), a four-part choir, corno da
caccia, oboe, oboe d'amore, two violins, viola and
basso continuo, I created this arrangement for Marimba