प्रकृतिं पुरुषं चैव क्षेत्रं क्षेत्रज्ञमेव च।एतद्वेदितुमिच्छामि ज्ञानं ज्ञेयं च केशव॥
prakṛtiṃ puruṣaṃ caiva kṣetraṃ kṣetra-jñam eva caetad veditum icchāmi jñānaṃ jñeyaṃ ca keśava
Word by word
The verse says
Arjuna said: Nature and the person, the field and the one who knows the field, knowledge and what is to be known — Krishna, I want to understand these.
In plain words
Three pairs, named as pairs.
Arjuna is not asking for a teaching this time. He is asking for a vocabulary.
And he is right to. The chapter ahead is the most technical in the book, and these six words are the whole of its machinery.
Where you've felt this · in study
You sit down with somebody to understand how your own pension works and the first thing you ask is what four of the words on the statement mean. Not because you want a lecture. Because every sentence after that depends on them, and nodding through would waste the afternoon.
Going deeper
Asking for definitions before an argument is the most efficient thing a student can do, and Arjuna has learned to do it.
He did the same at the start of Chapter 8, listing the technical terms Krishna had used and asking what each one meant. Here he goes further and asks for them in advance. Three pairs, each of which turns out to name the same distinction from a different angle.
That is worth knowing before the chapter starts. Nature and person, field and knower, knowledge and what is known — these are not six topics.
They are one line, drawn three times, between what is observed and whatever is doing the observing. Everything in the next thirty-four verses sits on one side of that line or the other, and a reader who holds on to that will not get lost.