According to Chapter 20, what is the role of a Guru in understanding profound spiritual texts like the Upanishads?

Chapter 20 strongly emphasizes the indispensability of a Guru for spiritual understanding. It states that the Upanishads contain the essence of the Vedas, a treasure that is very difficult to grasp without the grace of a Guru. The chapter warns that even a great scholar who tries to comprehend these texts through their own effort will fail, as the hidden truth is difficult to find at every step without a Guru's guidance. However, for a humble devotee attached to the Guru's feet, the hidden meaning opens up automatically, making the path of Self-knowledge and liberation from rebirth accessible.