According to Chapter 10, what is the role and significance of the Sadguru in a devotee's life?

Chapter 10 describes the Sadguru as the one eternal God, in contrast to other illusory gods. By placing faith in His feet, a devotee can have their fate changed, as the text states He "strikes a nail over the lines of destiny." The Sadguru is presented as a boatman who helps devotees cross the ocean of existence (Bhavasagar) and overcome the three types of miseries. According to the teachings in this chapter, pure service to the Sadguru completely destroys worldly existence (Samsara), and His mere sight can break the knots of the heart and destroy accumulated and current karmas.