J.S. Bach: “The aim and final end of all music should be none other than the glory of God and the refreshment of the soul.”
Samuel Hsu: "Bach is inexorable"
What is it about Bach's music that seems to be a reflection of perfect spirituality? Call it what you will, even those who do not find God in Bach's music, such as pianist Murray Perahia, acknowledge the organic and primordial qualities in his compositions. I agree with the statement that if no one came after Bach to continue the progress of Western music, it would have been enough. While most music seems to be an expression of the composer(or eventually the performer), the music of Bach is an expression of the heart of God. If all the sorrow, love, and peace of God could be combined into a piece of music, this would be it.
Bach of course uses melody, which would later become the main element of music as more personal expressions became important to composers. But there is something beyond melody in Bach. The figurations, sequences, and harmonic progressions get to the very essence of life. Consider this organ prelude below, which was arranged for piano by Alexander Siloti (while still preserving the integrity of the original).
Notice the right hand figuration. This simple figuration that seems to do nothing but outline the harmonic progressions continues throughout the entire prelude. Simple figurations over a "cantus firmus" (the melody, which you can see the beginning of in the top voice of the left hand). My piano teacher once told me that Bach is inexorable. This means there is something inside the music that is unstoppable, irresistable, going on until the very last chord (many parallels here could be drawn to the nature of God). Even despite pauses in the structure, it continues. Later classical music is almost always comprised of many phrases (kind of like sentences). This prelude could be viewed as one long phrase (Siloti worked in a repeat, which makes it seem like two parts).The beautiful thing about this kind of music is you can make it your own. You can create your own story for what it represents to you. Personally, when I hear it, I imagine God the Father looking at His Son, walking faithfully towards the cross, ready to die for humanity. All the sorrow He feels and at the same time, love for mankind.
The best performance I have found of this piece is by Emil Gilels. A Russian pianist that could stay authentic to what was on the page, but made every piece his own and it showed.
Bach-Siloti-Prelude in B minor - Emil Gilels
In this case, I preferred just the audio so as not to distract too much. But if you prefer the video, click HERE

