There are two classes of men within this world. In the Viṣṇu Purāṇa it is said that viṣṇu-bhaktaḥ bhaved daivaḥ (Padma Purāṇa). Those are viṣṇu-bhaktas, devotee of Lord Viṣṇu . . . three deities—Viṣṇu, Maheśvara and Brahmā. Brahmā, Viṣṇu, Maheśvara. So those who are devotees of Viṣṇu, they are devatā. Not that the asuras, just like Rāvaṇa. Rāvaṇa was a great devotee of Lord Śiva, and Hiraṇyakaśipu was great devotee of Brahmā, but both of them have been described as asura and rākṣasa. They are great devotees. Therefore the conclusion is there are two classes of men, asura and devatā. The viṣṇu bhaktaḥ bhaved daivaḥ, those who are devotees of Lord Viṣṇu, they are deva, devatā, or demigods, and asuras tad-viparyayaḥ. What is the difference between devatā and asura? The . . . that is explained by Kṛṣṇa, that daivī sampad vimokṣāya (BG 16.5). If you develop your divine qualities, as they're described, ahiṁsā, sattva-saṁśuddhiḥ . . . sattva-saṁśuddhiḥ. Sattva-saṁśuddhiḥ means existentional purification. Our . . . we, as spirit soul, we are pure originally, because Kṛṣṇa is pure. Arjuna accepts Kṛṣṇa, after understanding Bhagavad-gītā, paraṁ brahma paraṁ dhāma pavitram-paramaṁ bhavān (BG 10.12): "You are paraṁ pavitra." And God is paraṁ pavitra is admitted in the Īśopaniṣad: apāpa-viddham (ISO 8), asnāviram.
Asnāviram means in the body of God there are no veins, and so therefore apāpa-viddham. Veins, as soon as you have got this veins, that is material body. The body is maintained under certain material condition. You eat, and this eating substance transformed into secretion, then through the veins this comes to the heart, and heart it becomes red, corpuscle, the blood, the blood is diffused. Therefore there are so many channels, veins. And these things are pushed on with air, and if there is shortage of air circulation, the man becomes paralyzed. This is scientific.
So these things are required for the material body, not for the spiritual body. In spiritual body, asnāviram, there is no vein. Therefore one who misunderstands Kṛṣṇa as having a material body, he has been described in the Bhagavad-gītā as mūḍhā. Avajānanti māṁ mūḍhā mānuṣīṁ tanum āśritam (BG 9.11). He has no veins. There is no difference between His body and soul. We have got difference with our body and soul; therefore this existence with this material body is not śuddha, is not pure. Therefore, sattva-saṁśuddhir, abhayaṁ sattva-saṁśuddhir.
Śrīla Viśvanātha Cakravartī Ṭhākura has described this abhayam means fearlessness. Because unless I become fearless, I cannot give up my present position. Just like, according to our Vedic system . . . not our, everyone. Vedic system is for everyone. It is not that for a particular class of men, Vedic system. That's wrong. When Kṛṣṇa says, catur varṇyaṁ mayā sṛṣṭam (BG 4.13), this Vedic system, it is for all, not for a particular country, a particular society. So the Vedic system is that one should accept the order, sannyāsa order, at the last stage of his life. Suppose one lives for a hundred years. He should become brahmacārī, student, for twenty-five years, then a married man for another twenty-five years, and after fifty years, pañcaśordhvaṁ vanaṁ vrajet, he should accept the vana-vāsī. Vana-vāsī means vānaprastha. Vāna: from vana, vāna, "one who has gone to the forest," vānaprastha. So then, when he is prepared, he should take sannyāsa.
The whole institution is meant for sattva, sattva-saṁśuddhiḥ. So one has to purify his existentional life; otherwise, if he does not purify his existence, then he has to transmigrate from one body to another, and that is material existence. That is material existence. Jalajā nava-lakṣāni sthāvarā lakṣa-viṁśati (Padma Purāṇa). One has to transmigrate from lower species of life, aquatic life, to trees; from trees to insect; insect to birds; birds to beasts; and from beasts . . . that is evolution. That evolution is not Darwin's evolution. That evolution, it is called janmānta vāda. The soul is going from one body to another, not that the body is transforming. The Darwin's theory is that the body is transforming. No. Body cannot transform. Body can take the shape according to the desire of the soul, or according to the effects, resultant action, of one's karma.
So different types of bodies are all there. Just like, in Calcutta, there are different types of apartments. So you can take an apartment or purchase an apartment according to the price you pay. That is . . . that is evolution. If you can pay more, then you can get nice body, nice apartment. This body is apartment. Ūrdhvaṁ gacchanti sattva-sthā (BG 14.18). If you are regulated in the modes of goodness, sattva-sthā, sattva-guṇa, then you are promoted to the higher planetary system, higher system of life. Just like in the Bhagavad-gītā it is also said that śucīnāṁ śrīmatāṁ gehe yoga-bhraṣṭo sañjāyate (BG 6.41). One who is not mature in his performance of yoga, he is given chance, another chance—another chance in a very nice family, śucīnām, very pure brāhmin family; and śrīmatām, very rich, royal or very rich mercantile family. These are chances.