Bhagavad Gita 13.2
श्री भगवानुवाच। इदं शरीरं कौन्तेय क्षेत्रमित्यभिधीयते। एतद्यो वेत्ति तं प्राहुः क्षेत्रज्ञ इति तद्विदः।।13.2।।
śrī bhagavānuvāca| idaṃ śarīraṃ kaunteya kṣetramityabhidhīyate| etadyo vetti taṃ prāhuḥ kṣetrajña iti tadvidaḥ||13.2||
shri bhagavanuvaca idam shariram kaunteya kshetramityabhidhiyate etadyo vetti tam prahuh kshetrajna iti tadvidah13.2
Meaning
Krishna says: This body is called the field (Kshetra), and one who knows it is called the knower of the field (Kshetrajna). Understand this distinction between the body and the conscious entity within it.
श्रीभगवान् बोले — हे कौन्तेय! यह शरीर क्षेत्र कहलाता है, और जो इसे जानता है, उसे तत्त्वज्ञ जन क्षेत्रज्ञ कहते हैं।
This is verse 2 of 35 in Chapter 13 (Kshetra Kshetrajna Vibhaga Yoga) of the Bhagavad Gita.