What promise did Babasaheb Tarkhad make to his son to convince him to go to Shirdi?

To convince his son to travel to Shirdi, Babasaheb Tarkhad made a solemn promise regarding the daily worship of Sai Baba. The son's condition for going was that the Naivedya offering must continue. According to Chapter 9, the son stated, "Without offering Naivedya to Sai, no one should consume food at home." In response, his father gave a firm assurance, saying, "Go, I will offer Naivedya daily; be certain." He further solidified his promise by declaring, "Without first dedicating to Sai, no one will consume food. Take this word of mine as proof." It was only after receiving this guarantee that the son agreed to the journey.