What is the significance of the Bhagavad Gita verse quoted in Chapter 50, and what does the text mean by 'Avagraha'?

Chapter 50 references the thirty-fourth verse of the fourth chapter of the Bhagavad Gita to make a subtle point about ignorance. The verse is "Tadviddhi pranipatena pariprasnena sevaya | upadeksyanti te jnanam jnaninastattvadarsinah ||". The chapter explains that in the third line of this verse, an 'Avagraha' (a grammatical symbol in Sanskrit) can emerge before the word 'Jnana' (knowledge), which acts as an indicator of 'Ajnana' (ignorance). This linguistic point is used to introduce a discourse oriented toward ignorance, suggesting that one must first understand and remove ignorance before true knowledge, which leads to liberation, can manifest.