Erforsche mich, Gott, und erfahre mein Herz, BWV 136
(Search me, God, and know my heart), 136 is a church cantata by Johann Sebastian Bach. Bach composed the cantata in 1723 in Leipzig to be used for the eighth Sunday after Trinity. He led the first performance on 18 July 1723. The work is part of Bach's first annual cycle of church cantatas; he began to compose cantatas for all occasions of the liturgical year when he took up office as Thomaskantor in May 1723. The cantata is structured in six movements: two choral movements at the beginning and end frame a sequence of alternating recitatives and arias. The opening movement is based on a verse from Psalm 139; the closing chorale on a stanza from Johann Heermann's hymn "". The cantata is scored for three vocal soloists (alto, tenor and bass), a four-part choir, corno, two oboes, strings and basso continuo. History and words When Bach took up office as Thomaskantor (director of church music) in Leipzig in May 1723 on the first Sunday after Trinity, he began to compose cantatas for all occasions of the liturgical year. He wrote for the Eighth Sunday after Trinity. 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" (), and from the Gospel of Matthew, the warning of false prophets from the Sermon on the Mount (). An unknown librettist wrote the text, closely related to the prescribed gospel. His text is the first in a group of ten cantatas following the same structure of biblical text – recitative – aria – recitative – aria – chorale. The ten cantatas were dedicated to the 8th to 14th and 21st to 22nd Sunday after Trinity and the second Sunday after Easter. The opening chorus is based on , focused on the examination of the believer's heart by God. The closing chorale is the ninth stanza of Johann Heermann's hymn "" (1630) on the melody of "", which Bach used again in 1724 as the base for his chorale cantata . The Bach scholar Alfred Dürr concludes from the autograph that only the middle section of the third movements and the chorale were composed in 1723 with certainty. The other parts may rely on a former unknown secular or church cantata, according to the conductor John Eliot Gardiner. Scoring and structure The cantata in six movements is scored for three vocal soloists (alto (A), tenor (T) and bass (B)), a four-part choir (SATB), corno (horn, Co), two oboes (Ob), two violins (Vl), viola (Va) and basso continuo (Bc). One oboe is marked "d'amore" (Oa) in the autograph kept by the Staatsbibliothek zu Berlin. The duration is given as 21 minutes. Some scholars, including Dürr and Gardiner, believe that the second oboe part in the choral movements 1 and 6 should also be played by oboe d'amore. The title on the original parts reads: "Domin: 8 post Trinit: / Erforsche mich Gott, und