Everything belongs to Krishna; using it for His satisfaction makes it spiritual, not material.Listen — Srila Prabhupada Uvaca
Bhagavad-gītā 13.6–7 — September 29, 1973, Bombay 730929BG-BOMBAY [29:00 Minutes] Bg-13.06–07_730929BG-BOMBAY Prabhupāda: ...āny ahaṅkāro buddhir avyaktam eva ca indriyāṇi daśaikaṁ ca pañca cendriya-gocarāḥ icchā dveṣaḥ sukhaṁ duḥkhaṁ saṅghāṭaś cetanā dhṛtiḥ etat kṣetraṁ samāsena sa-vikāram udāhṛtam [Bg. 13.6-7] 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].