According to Chapter 10, what is the role of a Sadguru, and what benefits does a devotee receive by serving one?

Chapter 10 beautifully illustrates the role of a Sadguru using the analogy of a boatman. It states that just as one trusts a boatman to cross a physical ocean, one must place trust in a Guru to cross the ocean of existence (Bhavasagar). By placing faith in the Sadguru's feet, a devotee can have their destiny changed, as the Guru "strikes a nail over the lines of destiny." The chapter further elaborates that through the Guru's grace, devotees can overcome the three types of miseries—physical, mental, and divine. Ultimately, the service of a Sadguru destroys the cycle of worldly existence (Samsara) and leads to the effortless attainment of liberation (Moksha) and divine knowledge.