What is the overall theme and structure of Chapter 51 of the Shri Sai Satcharita as presented in the introductory verses?

Chapter 51 begins with invocations and praise for Sai as the illuminator of the Gita's meaning. The chapter's stated purpose is to sanctify both the speaker and the listener, with the text asserting that listening to the Sai Charitra makes both pure. It serves as a bridge, referencing the previous chapter's discussion on destroying ignorance by analyzing a key dialogue between Krishna and Arjuna from the Bhagavad Gita. As outlined in Chapter 51, the narrative then transitions to promise a marvelous account of how Kakasaheb was first established in Shirdi, delving into his past-life bonds, and also mentions that it will share three other stories to soothe the hearts of devotees.