prakṛtiṁ puruṣaṁ caiva
kṣetraṁ kṣetra-jñam eva ca
etad veditum icchāmi
jñānaṁ jñeyaṁ ca keśava
idaṁ śarīraṁ kaunteya
kṣetram ity abhidhīyate
etad yo vetti taṁ prāhuḥ
kṣetra-jña iti tad-vidaḥ
arjunaḥ uvāca-Arjuna said; prakṛtim-nature; puruṣam-the enjoyer; ca-also; eva-certainly; kṣetram-body; kṣetrajñam-knower of the body; eva-certainly; ca-also; etat-all this; veditum-to understand; icchāmi-I wish; jñānam-knowledge; jñeyam-the object of knowledge; ca-also; keśava-O Kṛṣṇa; śrī bhagavān uvāca-the Personality of Godhead said; idam-this; śarīram-body; kaunteya-O son of Kuntī; kṣetram-the field; iti-thus; abhidhīyate-is called; etat-this; yaḥ-anyone; vetti-knows; tam-him; prāhuḥ-is called; kṣetrajñaḥ-knower of the body; iti-thus; tat-vidaḥ-one who knows.
Arjuna said: O my dear Kṛṣṇa, I wish to know about prakṛti [nature], Puruṣa [the enjoyer], and the field and the knower of the field, and of knowledge and the end of knowledge. The Blessed Lord then said: This body, O son of Kuntī, is called the field, and one who knows this body is called the knower of the field.
Arjuna was inquisitive about prakṛti or nature, puruṣa, the enjoyer, kṣetra, the field, kṣetrajña, its knower, and of knowledge and the object of knowledge. When he inquired about all these, Kṛṣṇa said that this body is called the field and that one who knows this body is called the knower of the field. This body is the field of activity for the conditioned soul. The conditioned soul is entrapped in material existence, and he attempts to lord over material nature. And so, according to his capacity to dominate material nature, he gets a field of activity. That field of activity is the body. And what is the body? The body is made of senses. The conditioned soul wants to enjoy sense gratification, and, according to his capacity to enjoy sense gratification, he is offered a body, or field of activity. Therefore the body is called kṣetra, or the field of activity for the conditioned soul. Now, the person who does not identify himself with the body is called kṣetrajña, the knower of the field. It is not very difficult to understand the difference between the field and its knower, the body and the knower of the body. Any person can consider that from childhood to old age he undergoes so many changes of body and yet is still one person, remaining. Thus there is a difference between the knower of the field of activities and the actual field of activities. A living conditioned soul can thus understand that he is different from the body. It is described in the beginning-dehe 'smin-that the living entity is within the body and that the body is changing from childhood to boyhood and from boyhood to youth and from youth to old age, and the person who owns the body knows that the body is changing. The owner is distinctly kṣetrajña. Sometimes we understand that I am happy, I am mad, I am a woman, I am a dog, I am a cat: these are the knowers. The knower is different from the field. Although we use many articles-our clothes, etc.-we know- that we are different from the things used. Similarly, we also understand by a little contemplation that we are different from the body.