According to Chapter 39, what is the role of the Guru in the process of realizing Self-Knowledge?

The Guru plays an indispensable role in helping a disciple overcome Ignorance. As explained in Chapter 39, Knowledge itself cannot be taught, but a Guru provides the means to remove the veil of Maya and Ignorance that obscures it. The text states that the Guru's grace acts like an ointment applied to the eyes, which causes the veil of Maya to fly away, revealing the natural Knowledge within. The Guru's teaching is compared to a fire that is necessary to burn away the dross to reveal the pure gold within. The path to gaining this grace involves prostration, questioning, and service to the Guru.