According to Chapter 32, why is the grace of a Guru considered essential, even for those who have studied the scriptures?

Chapter 32 strongly emphasizes the indispensability of a Guru's grace for attaining true knowledge. Verse 17 explicitly states that even if one has exhaustively studied the Vedas, Vedangas, and other Shastras, all that learning is considered "mere chaff" without the Guru's grace. The chapter posits that the words from Sai Baba's mouth are so potent they can destroy sins and afflictions, similar to the purifying sight of the Ganga, and ultimately, as mentioned in verse 16, they cause one to see one's own Guru, which is the key to real understanding.