According to the provided text, what is the fundamental duty of a saint like Sai Baba, and how does he aid his followers?

The source material from Chapter 30 clearly outlines that the primary and "unavoidable" task for saints is the upliftment of their own devotees. Sai Baba accomplishes this by bestowing his grace, which is described as granting "inconceivable great power" and the profound knowledge of discrimination between Self and non-Self. The chapter suggests that a devotee's simple act of holding onto Sai's feet can lead to the dissolution of all sins. Furthermore, it assures that for any follower caught in difficulties, Sai alone is the ultimate giver of peace, reinforcing his role as a constant protector and guide.