According to Chapter 20, what is the role of a Guru in attaining Self-knowledge, and why is scholarly effort alone insufficient?

Chapter 20 strongly emphasizes the indispensable role of a Guru in the pursuit of Self-knowledge. It explains that scriptures like the Upanishads contain the treasure of the Vedas, but their hidden truths are extremely difficult to grasp. The text explicitly states that a scholar's effort alone is insufficient, and that even at the end of an era, they cannot comprehend the correct meaning without a Guru's grace. This is because Self-knowledge is a science that cuts through the cycle of birth and death, and only through humble attachment to a Guru's feet can the hidden meanings be revealed effortlessly.