According to Chapter 20, what is the significance of having a Guru when trying to understand profound spiritual texts?

Chapter 20 strongly emphasizes that a Guru's grace is indispensable for comprehending deep spiritual knowledge. The text explains that the Upanishads, which contain the essence of the Vedas, are very difficult to grasp without the grace of both God and Guru. It posits that a scholar attempting to understand these texts through their own intellect alone will fail, as the hidden truth is inaccessible without a Guru. For a devotee who is attached to the Guru's feet, however, the chapter states that this difficulty vanishes, and the hidden meanings of the science of Self-knowledge open up automatically.