Even in the context of the incredible riches of the 1st Jahrgang, the Cantata BWV 109 is one of the gigantic peaks of inspiration. Much of extraordinary quality is the psychological insight of his reading of the Gospel from John for the 21st Sunday after Trinity. The story is simple. A nobleman approaches Jesus and begs him to come to his house to cure his son who is dying. Jesus tells him to go home; that his son will live. The man says that he believes and goes home. He returns home to find his son well. He asks his servants when the son recovered his health and they tell him the time, the same as when he spoke to Jesus. From then on the man and his whole household believed. Bach’s path is to imagine what the man was thinking on his way home, before he found out that his son was cured. The whole cantata is about doubt. It uses as the New Testament reading for its opening chorus not the Gospel for the day but rather a passage from Mark concerning another miracle of Jesus, in which a man cries “I believe, help thou mine unbelief.”
This reading sets off a pattern of wavering faith that weaves itself throughout the cantata. Bach uses an elaborate almost Wagnerian system of motives, which advise us of the believer’s progress throughout the cantata.
The opening chorus begins with a melody of staggering dimensions. It is 16 bars of continuous unfolding melody that travels through intricacies of texture and harmony but never stops, never cadences, and finally winds down into the entrance of the chorus. The melody is pitched quite high and often has a corno da caccia doubling the tune, which is usually carried by the violins and oboes. This melody certainly stands for the voice of God, for the steadfastness of faith. Bach did something like this earlier in the 1st Jahrgang with the high horn part in the Cantata BWV 136. Here, however, its length and the enormous permutations that it undergoes throughout the course of the sixteen bars make for a unique gesture. The melody has in its inception large leaps that give it a broad arc and grandeur, but its continual spinning keeps re-energizing the material. Those leaping fifths and sixths have become, by the 12th bar a leap of a ninth. There is a wonderful moment later where we think we have come to the end and we have cadenced in the tonic. But the tune keeps spinning out for another three bars. It is as if Bach wants it never to stop.
The actual choral entrance uses the opening material, first in one voice, then the whole chorus. By this time we think that we know what this chorus is about. But suddenly at bar 22 the line is fragmented, chopped up and destroyed. Under this chorus fragmentation is a little appogiatura figure in the orchestra, first subtly introduced in a subsidiary instrument in the opening ritornello. This figure by now prominent and aggressive, functions almost as a signpost to the pilgrim’s progress. It will remain with us throughout the cantata. Almost is if to show us that we are dealing with an individual’s doubt in the context of a believing community, the texture of both the orchestra and especially the chorus is very erratic. Few choruses in all of Bach have so many moments where only one or two voices are singing. This creates a transparency of texture that gives Bach enormous opportunities for subtlety of harmony and counterpoint. The melismas of two voices create some of the most ravishing and revealing sounds in the whole piece. Listen to the passage on the text ‘help my unbelief” for the altos and the tenors accompanied by transparent playing of the opening motive. The “help my unbelief’ side of the father comes to the fore at the end of the piece with the melismas piling up over not the “belief “ motive but the appogiatura motive by this time aggressive and pounding. Although it closes with a complete statement of the opening sixteen bars, the movement thus ends in a state of great ambiguity.
The secco tenor recitative continues the wavering of belief. Forte phrases of assurance alternate with doubting piano phrases. The recitative begins in Bb and wanders through several keys until the remarkable cadence in E minor. Notice how the questioning voice ends on the dominant seventh chord which is then resolved only by the precipitous bass plunge down to low E.
The tenor aria #3 brings back the appogiatura motive, this time more prominent and menacing. It is combined with a manic dotted figure that becomes more and more extravagant throughout the melody. The voice line sings this same awkward and extreme theme, combined with hysterical triplets on the word “wanket”[wavering] The B section is even more remarkable. The text, ”Des Glaubens Docht glimmt kaum hervor,”(The wick of faith glows dimly) is imaginatively drawn by continual and progressively downward spiraling harmony. The last line “Die Furcht macht stetig neuen Schmerz” brings one of the most shocking chord progressions in all of Bach. The new grief is not only portrayed by the shocking cadence but the recapitulation of the A section after that cadence comes as an equal surprise.
The secco alto recitative #4 not only brings a voice of calm but modulates back to the relative major of the tonic key, d minor. The aria for alto with two oboes obbligato replaces the tempestuousness of the tenor aria with refulgence. The appogiatura, which has been always used in an ambiguous harmonic context, has here become normal. It is either portrayed as the Schleiffer or an appogiatura in a much more stable harmony. The wild dotted notes of the tenor aria and the jagged staccato lines of the opening chorus have become here rich and reassuring rapid scale passages. The whole aria projects a kind of abundance. Words of continuing doubt like “Wenn ihre Hoffnung hilflos liegt” are set with mellifluous and reassuring passagework played by the oboes underneath the held notes of the voice.
Instead of a simple four-voice final chorale, we are given a full- fledged choral fantasia on the tune “Durch Adams Fall.” We have seen, in the Orgelbüchlein setting of this chorale BWV 637, some of the most extreme and hair-raising chromaticism in all of Bach. Clearly that is not called for here. It is interesting that Bach goes to great lengths in this muscular and stringent setting to make the harmonic richness and detail sit in the background to the amazing rhythmic thrust and inexorable forward motion of the piece. The harsh marching theme of the two oboes is propelled into the next bar by the rushing sixteenths of the continuo at the end of the bar. In an amazing tour de force, the scale of the piece and the rhythmic solidity make us not notice that the modal chorale ends not in the tonic but the dominant. No modal piece in all of Bach ends with such finality.