How does Chapter 18 describe the nature and greatness of the Sadguru?

Chapter 18 opens with powerful praise for the Sadguru, describing Him as the supreme Eternal one and the very Truth of Brahman. The text explains that the Sadguru makes the Unperceivable, which is debated by the Vedas, effortlessly clear to His devotees. As this chapter details, approaching the Sadguru is compared to a salt doll entering the ocean—an irreversible merging where the individual self dissolves. Furthermore, receiving the Guru's grace is said to eliminate the false logic of 'mine' and 'thine,' fostering a state beyond ego and duality.