Prabhupāda: Kṛṣṇa has spoken about the kṣetrajña. Kṣetrajña means the knower of the body, as He has already explained, that "I know that this is my finger." I never say, "I finger." So this body is kṣetrajña, the field of activities, and the soul is the proprietor or worker within the body. That is called kṣetrajña. This is already explained. He tried to explain... Because there are many ladies, so he tried to explain in Hindi. So here in the next verse Kṛṣṇa says, kṣetra-jñaṁ cāpi māṁ viddhi: "I am also kṣetrajña. I am also one of the knower of the body." So what is the difference between the one kṣetrajña already explained, the soul, and this kṣetrajña, Kṛṣṇa? What is the difference between the two? That is explained here. Kṛṣṇa says that "I am also kṣetrajña." Kṣetra-jñaṁ cāpi māṁ viddhi sarva-kṣetreṣu bhārata: "But the distinction is that the individual soul is situated in that particular body, but I am situated in every body, all-pervading." Sometimes they commit mistake that ātmā and Paramātmā, they are the same, but that is not the fact. Here Kṛṣṇa explains very distinctly that "I am also ātmā, but I am Paramātmā." That is the distinction between God and us.
When Arjuna understood Bhagavad-gītā, he addressed Kṛṣṇa, paraṁ brahma paraṁ dhāma pavitraṁ paramaṁ bhavān (BG 10.12). Paraṁ brahma. They are anxious to realize Brahman, that I..., ahaṁ brahmāsmi. Ahaṁ brahmāsmi does not mean that "I am Paraṁ Brahman." I am individual part and parcel of Brahman. Similarly, ātmā, Paramātmā; īśvara, Parameśvara. We should understand this distinction between ātmā, Paramātmā; Brahman, Para-brahman; īśvara, Parameśvara. So in the Vedic literature it is said, īśvaraḥ paramaḥ kṛṣṇaḥ (BS 5.1). Īśvara. Īśvara means controller. Every one of us, we are controller, either I control over my family or in my office or in my country. In this way everyone is a controller. I may be a controller. Not may be; in my limited jurisdiction I am also controller. You are also controller. So I may be a little greater controller, you may be a smaller controller and somebody may be greater than me. So in this way, if you study controllers, different types of controller, you'll find there is junior and senior. The same person is senior controller in the family, but in the office he's a junior controller. The same person is junior and senior at the same time. Somewhere he is junior, somewhere he is senior. In this way, if you study all different types of controller, you'll see there is duality of controls. But when you approach somebody that He's simply controller—He's not controlled by others—that is Kṛṣṇa. This is analytical study of the Supreme Personality of Godhead.