How does the beginning of Chapter 19 characterize the Supreme Reality, or Brahman?

The start of Chapter 19 offers a grand and paradoxical description of the Supreme Reality, which it equates with Sai. This ultimate principle, Brahman, is said to be the object that resides in all things, from the most minuscule atom to the vastness of the universe. It is described as being simultaneously "subtler than the subtlest and greater than the greatest." The author of Chapter 19 expresses a deep yearning to give a tangible form and color to this formless reality in order to perceive it with physical eyes, setting a devotional tone for the philosophical discourse that follows.