Based on the beginning of Chapter 25, what is the significance of one-pointed devotion and the role of a Sadguru?

Chapter 25 opens by establishing that Sai Baba is the supreme embodiment of mercy who desires one-pointed devotion from his followers. It states that a devotee who is faithful and filled with devotion will not lack for anything in attaining their desires. The text reinforces this by quoting Krishna's words to Uddhava: "The Sadguru is indeed My own form." Therefore, one-pointed devotion is defined as the act of worshipping such a Sadguru with love. The chapter asserts that once this unwavering faith is established in a devotee, the Sadguru, like Sai, wards off all their misfortunes, removes their suffering, and grants their desired objects.