Can you elaborate on the difference between body-consciousness and the true nature of the Self as explained in the text?

Chapter 37 presents a stark contrast between these two states. 'Body-consciousness' is defined as the firm conviction that "Body is me, this is my wealth," and it is called the knot in the heart and the source of sorrow. The true Self, conversely, is described as being devoid of all specific qualities and beyond old age, birth, and death. It is ancient, eternal, and all-pervading like the sky. While all that is visible, like a dream, is ultimately non-existent, the Self is the true essence that exists beyond even the concepts of 'existence' and 'non-existence.' This all-pervading form is the true form of the Guru.