Based on the beginning of Chapter 42, what is the role of a Sadguru like Sai Baba in a devotee's life?

According to the introductory verses of Chapter 42, a Sadguru like Sai Baba serves as a guide to help devotees cross the metaphorical "river of worldly existence." He is described as a "Wish-fulfilling Tree (Kalpataru)" for his followers. The text emphasizes that by the light of the Guru's grace, the fear of worldly life is removed, unhappiness turns into happiness, and the door to ultimate liberation opens. Chapter 42 further states that by constantly remembering the Sadguru's feet, obstacles dissolve and the sorrows of life are forgotten, leading to the attainment of great holiness.