How is the ultimate reality, referred to as Brahman or the Supreme Being, characterized in Chapter 19?

In Chapter 19, the ultimate reality, or Brahman, is described in profound terms. It is said to be the object that resides in everything, from the smallest atom to the vast universe, being both "subtler than the subtlest and greater than the greatest." This Supreme Being, also called the Purusha, is positioned as being even subtler than the Unmanifest (Avyakta or Maya). It is the ultimate goal where the senses and mind finally find rest. The chapter explains that the individual Soul, which appears in the world, is like a reflection of this Pure Brahman, which remains changeless and untainted.