Based on the introduction to his story, how does Damu Anna exemplify the principle of 'one-pointed faith'?

Chapter 25 introduces the principle that with "one-pointed faith," Sai Baba wards off a devotee's misfortunes and grants their desires. Damu Anna is presented as a living example of this. The text describes him as a devotee who was "devoted to Sai's feet." His unwavering commitment is shown through his long-standing vow to provide a flag for the Ram Navami festival, which he fulfilled for many years with "uninterrupted love and devotion." The subsequent blessing of being granted sons after being childless is positioned as a direct result of this steadfast faith, illustrating the rewards of such devotion.