What does Chapter 20 teach about the importance of a Guru for understanding complex spiritual texts?

Chapter 20 strongly emphasizes the necessity of a Guru for spiritual understanding. It uses Das Ganu's difficulty with the Upanishads as an example, stating that the Upanishads contain the essence of the Vedas and are very difficult to grasp without the grace of a Guru. The text explicitly claims that a scholar's own efforts are insufficient and that the hidden truth will not be revealed even at the end of an era without a Guru's guidance. In contrast, for a humble and detached devotee who is attached to the Guru's feet, the chapter assures that there is no difficulty, as the hidden meaning opens up automatically.