Can you explain the role of the Guru and the mind in achieving non-duality as described in the source?

As detailed in Chapter 14, the mind is often trapped in duality because of inherent ignorance, delusion, and the perception of differences in attributes. This tendency of the intellect to establish duality is labeled as 'pure ignorance.' The path to achieving non-duality, or oneness, therefore requires a fundamental transformation of the mind. Chapter 14 emphasizes that the Guru's teachings are the catalyst for this change, as they bring about the purification of the mind. Through this mental purification, an individual can attain the state of their true nature, which is oneness with the partless Brahman that pervades all.