How did Damu Anna demonstrate his devotion to Sai Baba, and what personal blessing did he receive as a result?

Damu Anna, a wealthy devotee from Ahmednagar, showed his devotion through a long-standing vow. As Chapter 25 describes, he was responsible for providing one of the two large new flags for the annual Ram Navami festival procession in Shirdi. This was a vow he carried out for many years with 'uninterrupted love and devotion.' The text further explains that while Damu Anna had two wives, he was childless. His devotion was rewarded when, by receiving Sai's blessings, he was blessed with sons. This illustrates the book's assertion that Sai wards off the misfortunes of his devotees and grants their desired objects once faith is established.