What allegories does Chapter 19 use to explain the nature of Brahman, the Soul, and devotion?

Chapter 19 employs several profound allegories to explain complex spiritual ideas. To illustrate devotion, it compares a devotee's offering to performing Aarti to the sun with a small wick or offering a palmful of ocean water back to the sea, emphasizing that faith is what matters. To explain the nature of the Soul, the chapter uses the analogy of a crystal that appears to take on the colors near it but remains intrinsically pure and unchanged. This shows how the Soul, though appearing to be part of the world, remains untainted. Furthermore, as described in Chapter 19, the illusion of the ego is compared to mistaking a rope for a snake, highlighting the false superimposition of our identity onto the physical body.