The narrator Hemadpant decided to write a book about Sai Baba. What specific event in the first chapter inspired this decision?

In Chapter 1, the narrator Hemadpant recounts the profound impact the wheat-grinding incident had on him. He was initially filled with 'great wonder' seeing a detached saint like Baba performing the manual labor of grinding. His confusion turned to awe when he understood the inconceivable connection Baba created between grinding wheat and eradicating the cholera epidemic. Seeing this incomprehensible cause and effect and Baba's divine skill, Hemadpant felt a surge of love, which he compares to waves in an ocean of milk. This experience moved him so deeply that he felt compelled 'to sing the sweet story of Baba to his heart's content,' which directly inspired him to write the book.