Bhagavad Gita, Chapter 13, Verse 1

Arjuna said: Prakriti and Purusha, also the Kshetra and the knower of the Kshetra, knowledge, and that which ought to be known, these, O Keshava, I desire to learn.

A real, precise question opens this chapter, four specific terms named, not a vague request to understand more.

Arjun asks for exact definitions, nature, the field, the knower, and what actually counts as knowledge. Real precision like this sets the tone for the whole philosophical chapter ahead.