Much of the resource material available for this piece mentions that the last section mirrors the first, but they usually stop there. We have taken the anlogous measures and laid them out one above the other, and done a detailed comparison. Now while it is interesting to simply carry out this process for its own sake, the real dividends are gained when we see a change and ask ourselves “Why??” Because the answer is never just “Because” or “Because he felt like it” or "Because he is a genius and had a genius idea”. There is always an actual practical reason. And when Bach has a practical reason for going outside a box, even if it’s a box of his own devising, his solution is what displays his extreme facility and understanding of the material at hand and of the conventions of his time. And therein lies his genius.
This video begins by demonstrating how, once again, Bach can use the simplest compositional devices, such as an ascending arpeggio and a descending scale, to create a most beautiful little motif. We can see the influence of Bach's younger days as a chorister in the writing of this piece; there is some beautiful dovetailing of the lines, as would happen in choral music.
