“Du wahrer Gott und Davids Sohn”, BWV 23, was the second cantata that Bach presented in Leipzig as part of his audition to secure the job of Thomaskantor and city music director. Together with its sister Cantata 22, it was performed on Quinquagesima Sunday, 1723 (February 7th). A year after starting at his new post, Bach performed it again for Quinquagesima 1724 (February 20th) with some differences in orchestration, and possibly also between 1728 and 1731.
The extant performance materials for this cantata show that the piece was composed in Cöthen, except for the final chorale which seems to have been added once Bach had arrived in Leipzig for his examinations. While this piece was originally intended for performance before the sermon, Bach ended up composing Cantata 22 for that purpose, and decided to use “Du wahrer Gott” for after the sermon, during the Communion.
This Sunday’s Gospel, Luke 18: 31-43, includes the story of the healing of a blind beggar, whom Jesus and his disciples encounter on the side of the road as they travel to Jerusalem for the Passover. This narrative is the main subject of the libretto for Cantata 23, which was sent to Bach in Cöthen to set to music for the audition.
The unknown poet identifies the believer with the blind man of the Gospel story. The first movement casts the words of the blind man as those of the believer, asking Jesus for mercy, help and comfort. The recitative that follows continues the plea for help, references the road where the man was laying, and closes with a quote from the Genesis story of Jacob wrestling with God: “I will not let you go unless you bless me.” (Genesis 32:26). The third movement focuses on one’s eyes, building on the theme of blindness and sight. It opens with a reference to Psalm 145 (“Aller Augen warten […] auf dich” – “All eyes wait […] upon you”) and vows to have Jesus’ word be the center of their works.
The libretto, as provided to Bach, included only the first three movements. In order to bring unity to the two-cantata set, Bach selected and inserted the “German Agnus Dei” (Martin Luther, 1528) as a chorale setting to close the cantata, given its strong association with the Passion, which is the subjacent theme of Cantata 22. The line “Erbarm dich unser!” (“Have mercy on us!”) also connects nicely with the blind man’s plea to Jesus.
The cantata is scored for 2 oboes d’amore, strings, 4-part choir and basso continuo. The solo voices required are soprano, alto and tenor.
Perhaps inspired by St. Matthew’s version of the same story, which has two blind men (Matthew 20:29-34), Bach sets the opening movement as a duet for soprano and alto, accompanied by two oboes d’amore and continuo. Effectively it becomes a quintet, betraying the deep roots in chamber music that Bach had developed in Cöthen. Marked “Molt’ adagio” in a C (4/4) meter, and featuring constant sextuplets in the instrumental parts, it could be seen as evoking the slow pilgrimage of Jesus and the apostles through the difficult roads to Jerusalem. After the opening ritornello, the voices enter canonically, half a bar apart. Their lines create frequent dissonances and are full of appoggiaturas representing the plea of the blind man. Several key words like “Ewigkeit” (“eternity”), “Entfernung” (“distance”) and others are set to long, held notes for emphasis, and “erbarm dich mein” (“have mercy on me”) is a chain of descending sighing gestures.
The following bass recitative is set as an accompagnato, with three lines above the voice and the basso continuo: two oboes and first violin in unison, second violin, and viola. Bach subtly anticipates the closing chorale by giving the German Agnus Dei traditional melody to the oboes and first violin, while the bass articulates the second part of the blind man’s plea. A particularly touching moment comes towards the end, with beautiful melodic turns for the reference to Genesis.
The next movement involves the full forces, in a setting that is reminiscent of Bach’s secular cantatas from Cöthen. After the orchestral ritornello, the choir takes the reference to Psalm 145 (“Aller Augen warten, Herr / Du allmächtger Gott, auf dich”) and repeats it a total of seven times in a rondo-like structure, interspersed with segments of the believer’s prayer assigned to the tenor and bass soloists. A dance-like triple meter, and the switch to the key of D major, both help brighten the mood after Jesus performs the healing. The rondo structure is set up symetrically: two choral episodes, four prayer segments with three choral statements between them, and two additional episodes at the end.
In Leipzig, with its traditional observance of “tempus clausum” in Advent and Lent, Quinquagesima Sunday was the last instance of figural music in church before Palm Sunday. Bach takes the opportunity to make a powerful forward reference to the Passion, while also connecting this cantata to “Jesus nahm zu sich die Zwölfe”, which had just been heard before the sermon: he adds a chorale setting of the traditional German Agnus Dei, a hymn that was, of course, well known to the congregation. Scholars believe that this movement was taken from an unidentified previously composed cantata, probably from Bach’s Weimar years.
This chorale sets each invocation of the Agnus Dei differently. The first one, marked Adagio, presents the oboes with upward gestures and chromatically descending scales, while the strings deliver “sighs” in the form of descending appoggiaturas. The choir renders the text homophonically with the tune on the sopranos. For the second invocation, the tempo changes to Andante. This time Bach constructs a three-part canon with the tune: first the sopranos, then the oboes in unison, and lastly the first violin. The other voices accompany polyphonically doubled by the remaining strings. The third invocation has the tune in the sopranos, while the other voices weave counterpoint around it. The strings double the voices and the oboes, in unison, engage in a syncopated decoration high above the whole structure.
This chorale was reused by Bach as the closing movement in the second version of his St. John Passion, from 1725.
