Bach again takes the word "Trinity" literally and
constructs a scintillating trio. The
sixteenth-note accompanimental pattern derives
from the chorale, but then the chorale appears in
dotted quarters, two phrases on the lower manual,
two phrases on the upper manual; a phrase on the
upper, another on the lower, and it finally
appears in the pedal, echoed by the upper manual.
The registration never changes, but great variety
occurs due to Bach's cleverness.
Samples from Grace Lutheran Casavant recorded by Brett Milan.