According to Chapter 19, what is the fundamental nature of Sai and how does the author propose to worship this reality?

Chapter 19 describes Sai as the Supreme Reality, or Brahman, that resides in everything from the smallest atom to the vast universe, being subtler than the subtlest and greater than the greatest. The author expresses a heartfelt desire to give a form, color, and shape to this formless reality to behold it with physical eyes. This act of worship is compared to a devotee offering a small wick's light to the great Sun or offering a palmful of ocean water back to the ocean as an oblation. As this chapter explains, such acts may seem inappropriate, but the divine, like the Sun or Ocean, looks only at the devotee's faith and not the scale of the offering.