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

The story of Damu Anna, as framed in Chapter 25, is a quintessential example of the rewards of 'one-pointed faith.' The author prefaces the tale by stating, 'Once one-pointed faith is established, Sai wards off all the misfortunes of that devotee. He grants the desired objects and removes their suffering.' Damu Anna, a wealthy and devout follower from Ahmednagar, fits this profile perfectly. His long-standing, loving vow to provide a flag for the Ram Navami festival demonstrates his unwavering devotion. The subsequent mention that he was blessed with sons after being childless serves as the fulfillment of Sai's promise to those with such faith. Thus, his story is used to directly illustrate this core principle of devotion and divine reciprocity.