What specific act of Sai Baba inspired the author to write the Shri Sai Satcharitra, as mentioned in Chapter 40?

As detailed in Chapter 40, the primary inspiration for the author to begin writing this book came from witnessing a specific, wondrous act of Sai Baba. The text describes how Sai, a saint, would set up a grinding stone in Shirdi, spread His legs, and grind grain. This powerful image filled the author's mind with wonder and sparked a strong desire to describe all of Sai's deeds. The author believed that by chronicling such acts, the impurities and sins of those who read them would be destroyed. This chapter highlights that this specific scene of Sai grinding grain is "the root of this book."