According to Chapter 10, what is the role of the Sadguru in a devotee's life, and how can they impact one's destiny?

Chapter 10 profoundly explains the supreme importance of the Sadguru. It states that the Guru is the one eternal God, while all other gods are illusory. By placing unwavering faith in the Guru's feet, a devotee can have their fate changed, an act described as 'striking a nail over the lines of destiny.' The chapter further elaborates that the pure service of the Sadguru can completely destroy the worldly existence (Samsara), making intellectual struggles unnecessary. The Sadguru acts as a boatman, helping devoted bhaktas cross the three types of miseries and the ocean of existence, ultimately giving them the attainment of liberation effortlessly.