How does Chapter 10 explain the role and power of a Sadguru, like Sai Baba, in a devotee's life?

According to Chapter 10, the Sadguru is portrayed as the "one eternal God" with the profound ability to alter a devotee's destiny, a concept poetically described as being able to "strike a nail over the lines of destiny." The chapter explains that pure service to the Sadguru can completely destroy the cycle of worldly existence (Samsara) and that He acts as a boatman to help devoted bhaktas cross the three types of miseries. By seeing a devotee's faith, the Sadguru can place Knowledge (Samvitti) in their hands, grant the liberation of Moksha, and even destroy their accumulated (Sanchit) and current (Kriyaman) karmas, all of which is detailed in Chapter 10.