What is the primary subject matter and main teaching presented in Chapter 48 of the Sai Satcharitra?

Chapter 48 of the Sai Satcharitra primarily addresses a listener's question about whether Shri Sai is a Guru or a Sadguru. To answer this, the chapter provides a detailed explanation of the characteristics of a true Sadguru. As described in Chapter 48, a Sadguru is not defined by mere scriptural knowledge, control of breath, or pleasing talks. Instead, a Sadguru is one who possesses direct, full self-experience and can impart that to a disciple. The chapter emphasizes that a true Sadguru is egoless, selfless, and views the disciple with fatherly love, never desiring service or livelihood from them.