Based on Chapter 40, what inspired the creation of the Shri Sai Satcharitra and what is the relationship between a Sadguru and a devotee?

The inspiration for the Shri Sai Satcharitra, as mentioned in Chapter 40, was a strong desire that arose in the author's mind after witnessing Sai Baba's divine acts, such as grinding grain in Shirdi. The author believed that describing these deeds would destroy impurities and sins. The chapter also describes the profound relationship between a Sadguru and a devotee, stating that when one seeks exclusive refuge with devotion, the Sadguru grants them His own Guru-nature. This union is compared to a river meeting the ocean, where all differences dissolve and they become one in essence.