I read about Damu Shet Kasar. What led him to make a vow to bring a flag for Ram Navami?

Damodar Savlaram, also known as Damu Shet Kasar, was a devotee who was very sad because he had no son from either of his two wives. Chapter 0 recounts that on the advice of Madhavrao Deshpande's father-in-law, he came to get Maharaj's blessing. Maharaj gave his blessing, and as a result, Damu Shet had a son. This miracle solidified his faith in Maharaj completely. Out of immense gratitude, he took a vow to bring a new flag every year for the Ram Navami festival and also to feed all the Fakirs present on that day, a tradition which continued for years.