According to the source, what is the indispensable role of the Guru in a disciple's spiritual journey?

Based on the text from Chapter 26 of the Sai Satcharitra, the Guru's role is absolutely central and essential for spiritual realization. The chapter explicitly states, "In the world, only the Guru is capable of granting the knowledge of Truth to a disciple." The author prays to Baba to make his intellect turn inward and provide the discrimination to distinguish the eternal from the temporary. This is because, as the chapter notes, the disciple's mind is often clouded by nescience and false logic. True awakening from the illusion of Maya occurs specifically "when the time for awakening through the Guru’s word arrives," leading to the shining forth of non-dual bliss, a state unattainable without the Guru's grace.