What is the significance of the image of Sai grinding grain as described in Chapter 40?

The image of Sai grinding grain, as detailed in Chapter 40, is presented as the very inspiration for the Shri Sai Satcharitra. The author recalls the wonder-filled sight of the saint setting up the grinding stone, spreading His legs, and grinding grain. This specific act sparked a powerful desire in the author's mind to document all of Sai's deeds. The chapter explicitly states that this event "is the root of this book," signifying that the entire work grew from the author's conviction that describing such leelas (divine acts) would serve to destroy impurities and sins for those who read or hear them.