Based on Chapter 10, what is the significance and power of a Sadguru in a devotee's life?

According to the teachings in Chapter 10, the Sadguru is paramount and holds the power to completely alter a devotee's life and destiny. The text states that by placing faith in the Guru's feet, He "strikes a nail over the lines of destiny," effectively changing one's fate. The chapter describes the Guru as the one eternal God, unlike other gods who are deemed illusory. Serving the Sadguru is said to destroy the cycle of worldly existence (Samsara) and help a devotee overcome all physical, mental, and divine miseries. By the Sadguru's grace, liberation (Moksha) is effortlessly attained and accumulated karmas are destroyed.