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

Chapter 20 strongly emphasizes the indispensable role of a Guru in comprehending spiritual truths. It states that the Upanishads, which are the treasure and essence of the Vedas, are very difficult to grasp without the grace of both God (Hari) and a Guru. The chapter refutes the idea that a scholar can understand these texts through their own efforts, noting that the hidden truth will not be revealed. However, for a humble and detached devotee attached to the Guru's feet, the difficult path becomes easy, and the hidden meaning opens up automatically. This is described as the science of Self-knowledge.