J. S. Bach’s set of six concertos for the Margrave of Brandenburg (simply known as the “Brandenburg” concertos) are among the high points of Western music. If you’re not familiar with the first Brandenburg concerto, have a listen to this haunting selection, which is the second of the concerto’s three movements:
It has an other-worldly quality, doesn’t it? Mysterious, agonizing, and yet strangely beautiful at the same time. And the question we find ourselves asking in amazement time and again is: how does Bach do it?
As is often the case with Bach, the compositional features that create the immediate emotional sensation do so largely because they exhibit a degree of intentionality that practically cries out with a sense of being laden with meaning. And when we pursue what that meaning might be, the most mind-boggling symbolisms emerge. And this is Bach’s genius: not merely that he creates expressive sounds, and not merely that he is a master of complex symbolism, but that in Bach the two are inextricable: the meaning under the surface of the music largely gives rise to the direct emotional appeal of the surface.
So what significances underlie the communicative impact of this amazing movement? With Bach, it’s always helpful to start with observing striking or unusual features of the music, as this is often the key that unlocks the rest.
Musicians might perhaps have noticed an alarming modulation at 1:01 in the video above (measure 12 in the score). What Bach is doing, in technical terms, is turning what sounds like a vii0 4/2 of C minor into a vii0 7 of A minor. In layman’s terms, he is changing abruptly from one key to another that is shockingly distant. This is extremely atypical of Bach’s concerted writing. The effect it has is to disrupt the flow of the movement’s unfolding tonal structure, creating a tonal rift between what comes before and what follows. To understand the significance of where this rift falls in the movement, let’s have a look at the movement’s structure.
The movement consists of three cycles of very similar material and concludes with a short coda. Each of the three cycles consists of eight measures of imitative dialogue between solo oboe and solo piccolo violin, followed by three measures in which that texture is turned upside-down as the bass takes up the theme and the upper strings accompany. So essentially the structure is 3 cycles of 8+3, plus the final coda.
The tonal rift mentioned above occurs immediately after the first of these cycles, effectively cutting it off from the other two. This is striking, because exactly the same thing happens in the Adagio of the D-minor concerto for harpsichord (originally violin), BWV 1052.
Meaningful Thematic Overlap
In the midst of a concerto permeated with cross-symbolism (which you can read about in this earlier piece), the Adagio of BWV 1052 consists of 6 statements of a repeating bass line. The second statement concludes in C minor, and the chord that immediately follows is a jarring A-major dominant chord (measure 28), accompanied by large melodic leaps in all the voices, mostly dissonant. So once again, there is a rift falling at exactly the one-third point of the movement’s structure, and once again the prominent notes are C and A. Curious.
Against the pervasive cross-symbolism of BWV 1052 (which I won’t elaborate here), it is difficult to avoid the conclusion that this striking gesture represents a “cutting-off” of one third of the Trinity as Jesus hung on the cross for the sins of the world.
A Theology of the Passion in Brandenburg 1
Who is this Suffering Servant?
Given the striking similarities between the slow movements of BWV 1052 and Brandenburg 1, what do we find if we view the Brandenburg through the same lens? Of course, there is the image of one of the three Persons of the Godhead being cut off. And if the imagery of the tonal rift isn’t clear or convincing enough, we might also consider that the concerto is scored for three choirs of instruments—strings, winds, and brass—one of which, the brass, is “cut off” (that is, silent) during this second movement.
But Bach also clarifies more specifically who it is that is “cut off.” Remember the interval that defines the tonal rift in both this piece and in BWV 1052: A to C. This interval is a minor third (kleine terz), as if to symbolize the Son: One of the Three that has made Himself minor or small (klein), both in His stance of submission to the Father and, still more, in His radical humbling, lowering, and emptying of Himself when he took on human likeness and assumed the form of a servant.
But emphasizing the Son’s subordinate position alone can lead to theological errors, which Bach, fascinatingly, appears to take pains to avoid. If the tonal “cutting off” of one of the three cycles of 8+3 measures symbolizes the cutting off of God the Son on the cross, then it is fair to say that the three cycles appear to represent the Triune nature of God. In that case, a quick look at the properties of these three cycles might crystallize what Bach is conveying about the relationship of the subordinate Son to Father and Spirit: specifically, what misinterpretations he explicitly precludes.
We have already observed that all three cycles are 8+3 measures: they are of equal duration or “greatness.” Bach is countering Arianism: Christ, though subordinate in stance to the Father, is fully God, equal in nature to the Father and the Spirit. Second, we have observed that the three cycles of 8+3 are very closely related in musical material, such that we could say they share a common nature. Bach is countering tritheism: there are not three gods but One God with one nature, albeit in three Persons. And third, although these cycles are extremely interrelated, they are not identical. Bach is countering modalism: while God is one, He is yet three distinct Persons.
But I think Bach further expounds upon the nature of the cut-off Son through the dialogue between oboe and piccolo violin that permeates the movement. The reason I think Bach likely intends this dialogue to refer to the Son is because at the end of each of the three cycles the dialogue falls silent while the melody that had formed the backbone of this dialogue for the previous eight measures spends a musically atypical three measures (representing three days?) in the “depths,” being taken up by the bass instruments (0:44-1:00, 1:45-2:01, and 2:48-3:04 in the video). And through this “entombment,” the world is figuratively turned upside down: the lowly bass, which has been providing the plainest of accompaniments, is now “exalted” by being given the melody, while the soloistic upper voices are humbled to providing scant accompaniment.
If this “entombed” melody represents Jesus, whose submission to death turns the world on its head, then it seems significant that this melody is primarily expressed in the dialogue between the oboe and piccolo violin (which occupies the first 8 measures of each cycle of 8+3). Here’s what I think the significance is. The oboe is a wind instrument. In the Bible, the idea of “wind” and “breath” is deeply connected with the concept of “s/Spirit” (cf. Genesis 2:7, John 3:8), because both Greek and Hebrew use a single word for wind, breath, and s/Spirit (ruach in Hebrew, pneuma in Greek). So one of the two dialoguing instruments has distinctly “spiritual” overtones. The other, a piccolo violin, belongs to a family of instruments whose origins lay in dance music, which (especially in light of the somewhat Plato-influenced notions of “spirituality” that have influenced much Western religious thought) connotes something more “earthy” or human. Could it be that, in this dialogue between oboe and piccolo violin, Bach is representing the dual nature of Jesus as both God and man? Note also that the relationship between the oboe and violin is primarily imitative: in other words, the voices play the same material but not at exactly the same time; one voice follows another: they are distinct but yet profoundly in accord. Likewise, Jesus’s human and divine natures were not contradictory or irrelevant to one other: they existed in perfect accord as Jesus lived a God-powered sinless life as a man and died a God-sized death as a man when he willingly went to the cross, dreading its pain even while embracing it and scorning its shame, for the joy set before Him.
A Theology of Redemption
Following the conclusion of the last of the three cycles of 8+3, there is a virtuosic but agonized “cry” from the solo oboe (3:05-3:11 in the video). In light of the movement’s passion symbolism, could this represent Jesus’ crying out, “It is finished!”? After all, what cry was ever more agonized than that with which the Son of God lay down his life? And what cry was ever more virtuosic than the one by which Jesus triumphed in power at the moment of his apparent defeat in weakness, as death was put to death through death by a carpenter nailed to a piece of wood, and evil and brokenness were not merely stopped, and not even merely undone, but turned to greater redemptive ends? The world has never seen such virtuosity.
After this agonized, virtuosic cry, Christ gives up his spirit: the movement concludes with a Phrygian descent in the bass (d, c, B-flat, A), which is the motif that Bach’s tradition most closely associates with death. Interesting, then, that Bach’s treatment of this motif should entail an ascending line in the upper voice, culminating in a bright A-major chord marked forte (“strong”), perhaps foreshadowing the resurrection that is to come.
There is one final observation to be made. When the Phrygian progression concludes a movement, it tends to pull the harmony away from the tonal center (i) and toward the dominant (V) chord. So, for example, in a movement in D minor, the Phrygian descent (as it is typically used) progresses from a D-minor chord (i) down by step to A major (V), and thus the movement concludes on a chord different than the one that defines the movement’s key. But fascinatingly, that’s not what is happening in this second movement of Brandenburg 1—true, the movement has the key signature of D minor; and true, it ends on an A-major chord. But look at how the movement begins: on a sustained A-major chord that can’t be conveniently classified as merely the dominant of D minor; the movement therefore ends as it begins: on an A-major chord in a scalar context resembling D minor. What Bach is implying, then, is not the tonality of D minor but rather the modality of A Phrygian, which is highly atypical of his compositional practice.
By means of this highly unusual move, Bach delivers a striking message whose intentionality is made clear by the abnormality of the means he uses. Typically when the Phrygian progression closes a movement, it functions like an afterthought appended to the end of a movement, creating divergence from the initially-stated tonality. But because the Adagio of Brandenburg 1 is set in A Phrygian to begin with, the concluding Phrygian progression is not an afterthought that pulls the harmonic direction away from the initially-stated tonality; quite the contrary: it is an essential component of the movement’s structure; but more than that, the Phrygian conclusion is what the beginning of the movement has set up to be necessary for bringing unity, resolution, and coherence to the whole. And we are so unused to a concluding Phrygian progression functioning this way that it grabs our attention (at least, those of us accustomed to Phrygian progressions!) with quite a shock. And well it should, because that shock is how Bach draws our attention to its message: The death of Christ is not an afterthought! It’s not God’s “plan B,” diverging from his original intentions—redemption through the cross of Christ has been God’s sovereign plan from the beginning, so that the brokenness that mars this world could be turned to redemptive glory greater even than if that brokenness had never been.
 A score of this piece can be viewed here: http://www.free-scores.com/download-sheet-music.php?pdf=12809
 A note for musicians: Similar enharmonic respellings can be found in several of Bach’s free-form works (e.g. the “Chromatic” Fantasy and Fugue, BWV 903; the “Great” G-Minor Fantasy and Fugue for organ, BWV 542; and the “Confiteor” from the so-called Mass in B Minor, BWV 232). But it is extremely atypical of Bach’s concerted works, which typically feature more organically unified tonal schemes.
 The solo voice leaps up a minor 14th (i.e. an octave plus a minor 7th), the first and second violins each leap up an augmented octave (!), the continuo leaps down a minor 7th, and the viola leaps up a major 6th.
 This language of “cutting off” is found throughout Scripture (e.g. Isaiah 53:8).
 A note to musicians: I would ordinarily think that what I have just written sounds like I might be reading more into the music than Bach actually intended; except that the striking correlation with BWV 1052 suggests that Bach likely did attach significance to this emphasis on a minor third (and the same minor third in both instances) at precisely the point where a third of the movement is tonally “cut off.” If there is indeed significance to this gesture, as there certainly appears to be, the symbolism I have suggested is far and away the most probable that I can think of in light of Bach’s own theology and compositional practice.
 If this is Bach’s intention, then of course the symbolism is limited (as is true of almost any simile or analogy): Jesus’ full humanity consisted of more than merely a human body, so it is inadequate to reduce his human nature to merely his body; conversely, his divine nature consisted in more than his merely having a spirit (as all humans have a spirit). I readily acknowledge this and propose that Bach’s use of the oboe and piccolo violin is not intended to be didactic but merely representative (as “God is spirit,” but humanity is characterized by having a material body).
 For musicians: It should be noted, however, that Bach’s treatment of modality is influenced by tonal practice in several respects, including the function and succession of local harmonies as well as the deeper-level dispensation of keys (or at least scalar affinities) throughout the movement.
 For musicians: While examples of similar modified modality are occasionally found in Bach’s chorales, examples from his larger-scale forms are exceedingly rare. True, several of Bach’s minor-mode pieces (e.g. BWV 538, BWV 1001) include one fewer flat in the key signature than is typical of modern practice, but in the practice of Bach and his contemporaries, this often indicates nothing about the actual compositional fabric of the piece. At times (as in BWV 538 or Vivaldi’s RV 531) such a key signature will accompany an increased emphasis on the melodic minor scale (often with raised scale-degrees 6 and 7 in both ascending and descending passages); but in such cases the movements in question tend to retain a distinctly tonal feel, with their “final” (to borrow a term from modal theory) being approached by the standard tonal predominant-dominant-tonic progression. This is distinctly not the case in the Adagio of Brandenburg 1.