According to Chapter 20, what is the significance of a Guru in understanding sacred texts like the Upanishads?

Chapter 20 powerfully emphasizes the indispensable role of a Guru for true spiritual understanding. The text states that the Upanishads, which hold the essence of the Vedas, are incredibly difficult to grasp without the grace of both God and a Guru. It explicitly warns that a scholar who arrogantly believes they can comprehend these texts through their own intellect will fail, as the "hidden truth does not come to hand" without a Guru's guidance. Conversely, this chapter assures that for a humble devotee attached to the Guru's feet, there is no difficulty at all. For such a person, the profound meanings of the science of Self-knowledge open up automatically.