Kṛṣṇa is discussing kṣetra, kṣetrajñaḥ, jñāna and jñeya. So kṣetra... Idaṁ śarīraṁ kṣetram ity abhidhīyate. This body is the kṣetra. Ksetra means the field of activities. Just like a cultivator, he has got a certain portion of land, and according to the land, he is seeding, sowing the seeds of grains, and as he is working, he's getting the profit by agricultural product. Similarly, this body is a field, is field, and we are sowing the seed, karma, sowing the seed and getting the result. Karmaṇā daiva-netreṇa (SB 3.31.1).
Why we have got different types of bodies? Why we haven't got, everyone, the same type of body? Somebody is fat, somebody is very thin, somebody white, somebody black, somebody very beautiful, somebody very ugly. There are so many varieties of bodies. Why? Saṅghāṭa. This is combination, color combination. There are three guṇas. Prakṛteḥ kriyamāṇāni guṇaiḥ karmāṇi sarvaśaḥ (BG 3.27). As you are associating with the guṇa, you are getting different types of body.
That is, Kṛṣṇa is explaining here, that mahā-bhūtāny ahaṅkāra. The ahaṅkāra is very important thing. False ahaṅkāra and real ahaṅkāra. Ahaṅkāra means law of identity. "I am Indian," this is ahaṅkāra. "I am American," this is ahaṅkāra. "I am rich man," this is also ahaṅkāra. "I am poor man." There are so many ahaṅkāra, law of identification. So this ahaṅkāra is the basis of getting a type of body, and... This is the subtle basis, ahaṅkāra. Mano buddhir ahaṅkāra. There are eight material elements: bhūmir āpo analo vāyuḥ khāṁ mano buddhir eva ca (BG 7.4). That is stated in the Seventh Chapter. This earth, water, fire, air, sky, mind, intelligence and ahaṅkāra. This is creating my different types of body.
Kṛṣṇa therefore says, mahā-bhūtāny ahaṅkāro buddhir avyaktam eva ca. Avyaktam means the total material substance. Just like when you construct a house there are heaps of materials—some stone, some cement, some woods, some iron—and you combine together... Tejo-vāri-mṛd-vinimayam. This whole world is exchange of three things: teja, fire, vāri, means water, and mṛt, means earth. So what is this Bombay city? The Bombay city is a heap of tejo-vāri-mṛd-vinimayaḥ. And... Here is one expert engineer, he knows how to mix these three things, tejo-vāri-mṛd-vinimayam, exchange. If there was no stock of tejo-vāri-mṛd-vinimayam, you could not build such a nice city. But who is supplying the ingredients? Can you create earth? No. Can you create water? No. You cannot create. You are simply working. You are simply working hard mixing them, that's all. Tejo vāri-mṛd-vinimayam. You cannot create. That is not possible. The creator is God. The creator is God. That is stated in the Seventh Chapter, prakṛtir me aṣṭadhā. Me, Kṛṣṇa says, "It is mine."
So this is called illusion. We are using Kṛṣṇa's property, but we are claiming "our." That is called illusion. Therefore śāstra says, Veda says, īśāvāsyam idaṁ sarvam (ISO 1): "Everything belongs to God." You cannot create this big mass of water, sea, or ocean. That is not possible. Who has created? Somebody has created. That is stated in the śāstra. There is perspiration. This water is perspiration of Mahā-Viṣṇu. We can understand, because we are minute particle of Mahā-Viṣṇu, mamaivāṁśo jīva-bhūtaḥ (BG 15.7). So sometimes we perspire and create some water, say, half an ounce water. But if somebody has unlimited power to perspire and create water, where is the difficulty to understand? There is no difficulty. If you take it for acceptance that this vast mass of water has come from the perspiration of the Supreme Personality of Godhead, so there is nothing to deny this fact. Acintya-śakti. Acintya-śakti means inconceivable power. We have got inconceivable power. Because we are minute particle of God, we have also minute inconceivable power. We do not know how the hairs are growing, but the energy is there within me. Similarly, so many things come out from the inconceivable power of Kṛṣṇa. Therefore Kṛṣṇa claims, bhūmir āpo 'nalo vāyuḥ khaṁ mano buddhir eva ca, prakṛtir me aṣṭadhā (BG 7.4). Bhinnā prakṛtir me aṣṭadhā, "They are My separated energy."