Based on Chapter 48 of the Shri Sai Satcharitra, what is the fundamental difference between a teacher with mere verbal knowledge and a true Sadguru?

Chapter 48 of the Shri Sai Satcharitra draws a sharp distinction between a teacher with only verbal knowledge and a true Sadguru. It states that while some may please audiences with eloquent talks about Brahman or have vast scriptural knowledge, this is considered "verbally hollow" if it lacks personal realization. The chapter emphasizes that the crucial difference is direct self-experience. A teacher without this experience has nothing of substance to give a disciple. In contrast, a Sadguru is defined as one who possesses both complete verbal knowledge and the authority that comes from giving "direct, full experience," enabling them to truly enlighten their followers.