According to Chapter 48, what is the crucial difference between a teacher with only verbal knowledge and a genuine Sadguru?

Chapter 48 draws a clear distinction between a true Sadguru and a teacher who possesses only verbal knowledge. The chapter describes the latter's knowledge as 'verbally hollow' if it is not backed by self-experience, even if their explanations are sweet and their knowledge seems vast. Such teachers might give mantras, but there is no certainty of the outcome. In contrast, Chapter 48 asserts that a genuine Sadguru is a 'giver of direct, full experience' and has the authority to truly enlighten disciples. The text firmly states that one who has no direct experience themselves has nothing to give a disciple and should never be called a Sadguru.