According to Chapter 40, what specific act of Sai Baba inspired the writing of the Shri Sai Satcharitra?

Chapter 40 reveals the root inspiration for the Shri Sai Satcharitra. The author recalls the image of Sai Baba, a saint, sitting in Shirdi with the grinding stone. The text vividly describes, "Setting up the grinding stone and spreading Your legs, You, a saint, would grind the grain; fixing the handle and pouring the grain—it fills my mind with wonder." This specific, humble act sparked a strong desire in the author's mind to describe all of Sai's deeds, believing that by doing so, his own impurities and sins would be destroyed. Therefore, this simple yet profound scene is identified in the chapter as the foundational moment that led to the book's creation.