How does Chapter 10 describe the role and power of a Sadguru in relation to a devotee's destiny and worldly struggles?

Chapter 10 of the Shri Sai Satcharitra portrays the Sadguru as the one eternal God, capable of altering a devotee's very fate. It states that by placing faith in His feet, He 'strikes a nail over the lines of destiny.' The chapter also describes the Guru as a boatman who ferries devoted bhaktas across the 'ocean of existence' (Bhavasagar), helping them overcome the three types of miseries: physical, mental, and divine. Pure service to the Sadguru is said to completely destroy the worldly existence (Samsara), making intellectual struggles unnecessary for spiritual progress.