Can you explain the philosophical connection between the Guru, Brahman, and the path to self-realization?

Chapter 45 presents a profound philosophical view where the Guru is equated with the ultimate reality, Brahman. The text posits that 'Brahman is eternal, the world is transient; the Guru alone is the true Brahman.' The path to self-realization, therefore, involves renouncing the transient world, which gives rise to dispassion (Vairagya), and meditating solely on the Guru, who is a 'solid mass of Brahman-consciousness.' This constant focus leads to what is called 'undifferentiated worship' (Abheda-bhajan), where divinity is perceived in all beings. As Chapter 45 explains, this practice allows the seeker to transcend the individual self and attain the bliss of self-realization.