Cantata 136, Erforsche mich, Gott, und erfahre mein Herz

Eighth Sunday after Trinity, July 18, 1723

When Bach took up his new position in Leipzig, he clearly sought to impress the town’s churchgoers with performance of his cantatas in the Sunday and feast day services. As discussed in several of the previous blog posts, beginning with Cantatas 75 and 76, Bach did so not only through exquisite compositional craft, but also by presenting cantatas with 10 or more movements in two parts. In these early weeks of Bach’s tenure, the Leipzig congregation frequently heard the first part of the cantata in its regular slot after the Gospel and the second part after the sermon.

Bach, however, did not continue these larger-scale cantatas in two parts and instead returned for the most part to a more typical scale of a cantata in one part (after the Gospel) and 6-8 movements. This could have been because Bach felt he had sufficiently impressed the Leipzig congregations, or perhaps the pace of producing a new cantata on such a large scale was unsustainable. Another contributing factor could be that the Sundays after Trinity, known as “Ordinary” time, contained very few feast days requiring grander music. Whatever the reasons, Bach largely stuck to a presenting a single, smaller-scale cantata beginning with Cantata 136, Erforsche mich, Gott, und erfahre mein Herz, for the Eighth Sunday after Trinity, July 18, 1723.


The starting point for considering every Bach church cantata is the Gospel for the day, the passage from the biblical books of Matthew, Mark, Luke, or John that was designated as the focus for that liturgical occasion. The Gospel readings were assigned by Martin Luther and largely consistent with the medieval liturgy on which he based his church reforms. Unlike the modern Revised Common Lectionary that uses a three-year cycle, the readings in Bach’s time were on an annual cycle so that the same Gospel reading returned each year for a particular liturgical occasion.

The Gospel for the Eighth Sunday after Trinity is Matthew 7:15-23, a passage that comes near the end of Jesus’s Sermon on the Mount recorded in Matthew 5-7:

Seht euch vor vor den falschen Propheten, die in Schafskleidern zu euch kommen, inwendig aber sind sie reißende Wölfe. An ihren Früchten sollt ihr sie erkennen. Kann man auch Trauben lesen von den Dornen oder Feigen von den Disteln?Also ein jeglicher guter Baum bringt gute Früchte; aber ein fauler Baum bringt arge Früchte.Ein guter Baum kann nicht arge Früchte bringen, und ein fauler Baum kann nicht gute Früchte bringen.Ein jeglicher Baum, der nicht gute Früchte bringt, wird abgehauen und ins Feuer geworfen.Darum an ihren Früchten sollt ihr sie erkennen. Es werden nicht alle, die zu mir sagen: HERR, HERR! ins Himmelreich kommen, sondern die den Willen tun meines Vaters im Himmel. Es werden viele zu mir sagen an jenem Tage: HERR, HERR! haben wir nicht in deinem Namen geweissagt, haben wir nicht in deinem Namen Teufel ausgetrieben, und haben wir nicht in deinem Namen viele Taten getan?Dann werde ich ihnen bekennen: Ich habe euch noch nie erkannt; weichet alle von mir, ihr Übeltäter! (Biblia, Das ist, Die gantze Heilige Schrifft Alten und Neuen Testaments, Verteutscht durch D. Martin Luther, 1545).

‘Beware of false prophets, who come to you in sheep’s clothing but inwardly are ravenous wolves. You will know them by their fruits. Are grapes gathered from thorns, or figs from thistles?In the same way, every good tree bears good fruit, but the bad tree bears bad fruit. A good tree cannot bear bad fruit, nor can a bad tree bear good fruit. Every tree that does not bear good fruit is cut down and thrown into the fire. Thus you will know them by their fruits. Not everyone who says to me, “Lord, Lord”, will enter the kingdom of heaven, but only one who does the will of my Father in heaven. On that day many will say to me, “Lord, Lord, did we not prophesy in your name, and cast out demons in your name, and do many deeds of power in your name?” Then I will declare to them, “I never knew you; go away from me, you evildoers”.’ (New Revised Standard Version)

When Christians today think about Jesus’s Sermon on the Mount, they today might tend to think of his words of blessing in the Beatitudes (Matthew 5:1-11); the Lord’s prayer (Matthew 6:9-13); Jesus’s assurance that the Christian should not worry but trust God and seek God’s kingdom (Matthew 6:25-34); or the promise that God will give good things to those who seek God (Matthew 7:7-11). In light of these comforting passages, the Gospel for the Eighth Sunday after Trinity can sound rather harsh to the modern ear. But it is not interpreted this way in either Lutheran theologian Johann Olearius’s Evangelischer Glaubens-Sieg der Kinder Gottes (1672) or in Cantata 136. Both offer comfort and assurance for those believe in Jesus as Son of God and Savior.

Although Olearius begins his reflection on Matthew 7:15-23 with the Gospel’s warning against false prophets and hypocrisy, he quickly reminds the reader that these words come from Jesus: “Who is speaking here? Namely our highly praised Christ Jesus who makes us blessed, the great prophet, the all-knowing ruler (Isaiah 9:6), the true good shepherd (John 10:11-17), who cares so sincerely for our salvation, and faithfully warns us against all harm and temptation” (983).

Olearius states that Jesus included this passage in the Sermon on the Mount in order to warn Christians against false prophets who would lead them away from the true Gospel. Olearius highlights the importance of knowing God through the Bible, the church, and the Eucharist. He states that the Christian can know, believe, and hope in God’s promises and recognize as false anything that is opposed to God’s truth (984).

In contrast to the false prophets, Olearius writes that the true Christian is the one who does God’s will, as Jesus explains in John 6:40: “This is indeed the will of my Father, that all who see the Son and believe in him may have eternal life; and I will raise them up on the last day.” Thus, the true prophet is the one who proclaims that God is so gracious and merciful that God sent his Son, Jesus, to the world for our salvation (988).


Readers can find the full German text of Cantata 136 here: English translations in the following discussion are from this site, by Michael Marissen and Daniel R. Melamed,

In interpreting the Gospel for the Eighth Sunday after Trinity, the text of Bach’s Cantata 136 similarly begins with warnings against false teachings but concludes focusing on the Christian’s salvation through the blood of Jesus Christ. The unidentified poet follows a text pattern common in many of Bach’s church cantatas: Bible verse, recitative, aria, recitative, aria, hymn stanza.

The cantata begins with the quotation of Psalm 139:23, which in the New Revised Standard Version reads, “Search me, O God, and know my heart; test me and know my thoughts.” Read out of context, it could be heard as the psalmist declaring their innocence and willingness to face the God’s judgment, especially if linked with the following verse, “See if there is any wicked way in me, and lead me in the way everlasting.” But Marissen and Melamed indicate that Martin Luther’s German translation instead points the reader to the preceding verses, in which the psalmist declares hatred for those who oppose God (fn. 2; Psalm 139:21-22). They translate movement 1 as: “Examine me, God, and know my heart; test me and know how I am resolved [to hate those who hate you].”

This reading makes clearer sense in the context of Cantata 136, with its focus on false prophets, named in the movement 2 recitative as “the children of hell,” who “Masquerade as angels of light” (lines 7-8). The recitative borrows much language from Matthew 7:15-23, but begins with a reference to the sin of Adam and Eve in Genesis 3 and the curse that came upon the earth because of it (Genesis 3:17-18). It further references the Christian theological understanding that, as a result of Adam and Eve’s original sin, all humans are beset by sin and the curse (lines 2-4). Thus, it continues, humans cannot help opposing God, because of “the corrupted essence [of human nature]” (line 9).

The recitative ends by pronouncing a future judgment for “the children of hell,” a theme that is expounded in the movement 3 aria. In referencing a day of judgment that will come upon God’s enemies, the poet invokes the biblical “day of the Lord.” Marissen and Melamed note that this aria references Joel 2:1, which concludes “Let all the inhabitants of the land tremble, for the day of the Lord is coming, it is near.”

After such dire warnings of God’s judgment in its first three movements, the cantata shifts momentously in lines 3-5 of the movement 4 recitative:

   But whoever is purified through Jesus’s blood,
   United with him in faith,
   Knows that he [the Lord] will pronounce no harsh judgment upon him.

Here is the heart of the Lutheran understanding of the Gospel, that through the blood of Jesus, God will be merciful to the Christian believer. The Christian is declared righteous through the blood of Jesus and will not suffer judgment. The recitative’s final two lines declare of the Christian:

   In Christ he indeed has
   Righteousness and strength.

The movement 5 aria continues these themes. It declares that while sin affects all persons because of Adam’s fall, the Christian is purified through the blood of Jesus. The cantata’s final movement expresses these same ideas by quoting stanza 9 of Johann Heermann’s hymn, Wo soll ich fliehen hin? (1630).

The poetry of Cantata 136 does not have much subtlety to it: the first three movements focus on God’s judgment on false prophets, while the last three focus on salvation for the Christian believer through Jesus’s blood. The cantata is notable for its fairly simple declaration of key Lutheran theology: that curse and judgment come as a result of the original sin of Adam and Eve, but salvation comes through believing in Jesus Christ.