According to Chapter 25, what is the principle of one-pointed devotion and what are its results?

Chapter 25 explains that Sai Baba, as an embodiment of mercy, desires only one-pointed devotion from his followers. This concept is defined through a reference to Krishna's words to Uddhava, stating that the Sadguru is God's own form and that worshipping the Sadguru with love is the essence of one-pointed devotion. The chapter promises significant results for those who achieve this state of faith. It explicitly states that a devotee who is faithful and filled with such devotion will lack nothing in attaining their desires. Once this unwavering faith is established, Sai Baba personally intervenes to ward off all of that devotee's misfortunes, remove their suffering, and grant them their desired objects.