What promise did Babasaheb Tarkhad make to his son before his son left for Shirdi, and why was this promise necessary?

Babasaheb Tarkhad's son was a devout follower of Sai Baba who performed daily worship, including offering Naivedya (food offering) to a photograph of Sai. As detailed in Chapter 9, when the son and his mother planned a trip to Shirdi, the son was deeply concerned about who would continue this daily ritual. He was hesitant to entrust this duty to his father, who was a follower of the Prarthana Samaj and not accustomed to idol worship. To overcome this hurdle, the son requested his father to promise that no one in the house would eat before the Naivedya was offered to Sai. Chapter 9 states that Babasaheb gave his word, saying, "Go, I will offer Naivedya daily; be certain." This assurance was the essential condition that allowed the son to proceed with his journey in peace.