Summary
Krishna distinguishes between the Field (the body/matter) and the Knower of the Field (the soul/consciousness).
Verse 2
इदं शरीरं कौन्तेय क्षेत्रमित्यभिधीयते । एतद्यो वेत्ति तं प्राहुः क्षेत्रज्ञ इति तद्विदः ॥
idaṃ śarīraṃ kaunteya kṣetram ity abhidhīyate | etad yo vetti taṃ prāhuḥ kṣetrajña iti tad-vidaḥ ||
O son of Kunti, this body is also called the field, and one who knows this body is called the knower of the field.