The real explanation is that because we are little Kṛṣṇa . . . just like the father and the little child, if there is fight, the father may come out victorious, the child may become overwhelmed, similarly, we are also Kṛṣṇa, a small particle of Kṛṣṇa, but some way or other, when we come in touch with this material world, we contact either of the three modes of material nature, sattva-guṇa, rajo-guṇa, tamo-guṇa, and according to our association with the particular type of nature, we get a different type of body. Kāraṇāṁ guṇa-saṅgaḥ asya sad-asad-janma-yoniṣu (BG 13.22).
Why there are different types of living entities, different types of bodies? That is explained in the Bhagavad-gītā. Kāraṇam, the cause, the reason is, guṇa-saṅgaḥ asya. Guṇa saṅgasya. So we are gold, but some gold has fallen in the mud, some gold has fallen in the water, some gold has fallen on the grass. These are examples. They are very much nicely explained in the Vedic literature. Sometimes the living entity is considered as the spark of fire. You have seen the sparks of fire. So the fire, original fire, is never covered by māyā or darkness. But the small particle of fire, which are called sparks, they, as soon as come out of the fire, they are extinguished. No more, I mean to say, sparking.
So this is our position. Although we are part and parcel of Kṛṣṇa, sanātana, eternally . . . Manaḥ-ṣaṣṭhāni indriyāṇi prakṛti-sthāni karṣati. Because on account of our material mind . . . material mind means the mind is absorbed in the thought of enjoying this material world. This is the beginning of our material disease. Manaḥ-ṣaṣṭhāni indriyāṇi (BG 15.7). Then according to the mind, we develop different senses, and we are trying to enjoy this material world in different type of body. That is our material disease. Manaḥ-ṣaṣṭhāni indriyāṇi prakṛti-sthāni karṣati.
Therefore the whole Vedic literature is meant for reminding us about our original position. That is explained in the Caitanya-caritāmṛta. Kṛṣṇa . . . anādi bahirmukha jīva kṛṣṇa bhuli' gela. We have forgotten Kṛṣṇa, anādi. Anādi means we do not know when we did forgot, but we have forgotten our relationship. Anādi bahirmukha jīva kṛṣṇa bhuli' . . . ataeva kṛṣṇa veda-purāṇa karilā. These Vedas and thePurāṇas, they are meant for reminding us, to give us information that "You are not this material body. You are not Indian, you are not American, you are not brāhmin, you are not śūdra. You are eternally part and parcel of Kṛṣṇa. So your business is to serve Kṛṣṇa." This is the purpose of all Vedic literature. Vedaiṣ ca sarvair aham eva vedyam (BG 15.15).