What does Chapter 20 teach about the role of Guru's grace in understanding profound scriptures?

Chapter 20 strongly emphasizes that a Guru's grace is indispensable for understanding profound spiritual texts like the Upanishads. It argues that these scriptures, which hold the essence of the Vedas, are "very difficult to grasp" without the grace of both Hari (God) and a Guru. The chapter explicitly refutes the idea that a scholar can comprehend these texts through their own efforts, stating this "will not happen even at the end of an era" because the path is difficult at every step. Conversely, as explained in Chapter 20, for a devotee attached to the Guru's feet, "there is not even a bit of difficulty," and the hidden meanings of the scriptures open up automatically.