Why is a Guru considered essential for removing ignorance, even for a person who might be considered wise?

A Guru is presented as indispensable because wisdom alone can be corrupted by doubt. Chapter 50 explicitly states that ignorance, which arises from doubt, "cannot be removed without a Guru." The text uses the powerful example of Shuka, a "supreme knower," who still suffered a loss due to doubt ('vikalpa'). This illustrates that intellectual or even spiritual knowledge can be compromised. When doubt enters knowledge, it can lead to pride. Moreover, the text notes that a person who is 'wise' but still attached to wealth, family, and sense enjoyment is deluded and their knowledge is covered by ignorance. A Guru's role is to guide the student past these pitfalls of pride and attachment, remove the foundational doubt that perpetuates ignorance, and purify the mind so that true, unblemished knowledge can manifest.