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

Chapter 10 powerfully emphasizes the central role of the Sadguru, stating that while other gods are illusory, the Guru is the one eternal God. By placing sincere faith in the Sadguru's feet, a devotee can have their destiny changed, an act described as 'striking a nail over the lines of destiny.' The chapter uses the analogy of a boatman, explaining that a Guru is essential to navigate the 'ocean of existence' (Bhavasagar). For devoted bhaktas, the Sadguru becomes their boatman, helping them overcome the three types of miseries. Ultimately, the Sadguru sees the devotee's faith and grants them Knowledge (Samvitti) and the bliss of liberation (Moksha) effortlessly.