Bhagavad Gita 13.1
इदं शरीरं कौन्तेय क्षेत्रमित्यभिधीयते। एतद्यो वेत्ति तं प्राहुः क्षेत्रज्ञ इति तद्विदः॥
idaṁ śarīraṁ kaunteya kṣetram ity abhidhīyate etad yo vetti taṁ prāhuḥ kṣetrajña iti tad-vidaḥ
Translation
This body, son of Kunti, is called the field. He who knows it, those who know that call the knower of the field.
Reflection
Pick one sensation right now. Is it field, or is it the knower?
Read this verse in its chapter: Chapter Thirteen
Two words open the chapter and carry it. Body is kshetra, a field. The one who knows the body is kshetrajna, the knower of the field. Field gets worked. Knower watches the working. Identification slides between them without noticing, and most suffering rides on that slide. The verse asks for a clean separation up front. What is worked on, what does the working. Skin, breath, mood, thought, mood again. These belong to the field. Whatever sits behind noticing them belongs to the knower. The chapter will keep returning to this distinction with different vocabularies. First move: pick one sensation right now and observe which side of the line it sits on.