How does Chapter 20 explain the importance of a Guru in understanding complex scriptures like the Upanishads?

Chapter 20 strongly emphasizes the indispensable role of a Guru for spiritual understanding. It uses the example of the Upanishads, which are described as the 'treasure of the four Vedas,' to illustrate this point. The chapter states that without the grace of Hari (God) and the Guru, grasping their meaning is 'very difficult.' It warns that a person, no matter how scholarly, cannot comprehend the hidden truth of these texts by their own efforts, as the path is 'difficult at every step.' Conversely, as Chapter 20 explains, for a devotee who is attached to the Guru's feet, there is no difficulty at all, and the hidden meaning reveals itself automatically.