Prabhupāda:
- kāṅkṣantaḥ karmaṇāṁ siddhiṁ
- yajanta iha devatāḥ
- kṣipraṁ hi mānuṣe loke
- siddhir bhavati karmajā
- (BG 4.12)
Generally, people are karmajā. Karmajā means one who wants to enjoy the fruit of his labor. Everyone in this material world, they have come to enjoy. So therefore they are working so hard. We have seen in big, big cities, especially in the Western world, they are working very, very hard. In the Śrīmad-Bhāgavatam it is said that nūnaṁ pramattaḥ kurute vikarma.
- nūnaṁ pramattaḥ kurute vikarma
- yad indriya-prītaya āpṛṇoti
- na sādhu manye yata ātmano 'yam
- kleśada . . . asann api kleśada āsa dehaḥ
- (SB 5.5.4)
People do not understand that because we have got this material body, the sufferings are there. We are spirit. Ahaṁ brahmāsmi. We are all spirit soul. But somehow or other, some way or otherwise, we have contacted this material world, and we are bound up by our karma, or fruitive result of fruitive activities. And the result is this body. Karmaṇā daiva-netreṇa jantur dehopapatti (SB 3.31.1).
We work in a certain way, in contamination with the modes of material nature, and we get different types of body. These are explained in the Bhagavad-gītā, that why there are different types of body. Now we are sitting, say, one hundred men here. We have got different types of body. Not that everyone's body of the same type. Why? Why the scientists cannot reply this? But Bhagavad-gītā replies. What is the reply? The reply is kāraṇaṁ guṇa-saṅgaḥ asya sad-asad-yoni-janmasu (BG 13.22). We have got different types of body from different types of mother. So kāraṇaṁ guṇa-saṅgaḥ asya. Mother means yoni, and father means bīja. Yathā yoni yathā bījam (SB 6.1.54). Our birth is taking place according to the mother and the father. Yathā bījaṁ yathā yoni. So we are getting different types of body, human body or animal body or demigod body. This is due to kāraṇam.