We've experienced in our practical lifetime that we were very tiny, youth; we had a small body, child's body: kaumāraṁ yauvanam. Then youthful body, then we're having old man, old woman's body, like this. So practically speaking, this body is constantly changing. Although Kṛṣṇa gives this example because He is trying to explain a very fine point of understanding, namely transmigration of the soul: that in reality the body that we have is changing at every moment, at every instant. But we cannot see that because our consciousness is not so sharp to pick up when there's change of body. But Kṛṣṇa explains, "You can see that you had a small body, now you have a youthful body, now you have an old man's body." Actually there is a continuum of change at every moment. So this is the changing material body, and the mind likewise is changing. But the soul, the living entity, is not changing, and this is experienced practically by the fact that in spite of so many changes of body that we had, we're still the same person. Just like we can remember when we were young children playing in the park or at the streets, and then older, older, older; going to school; older, family life; older, now retired; now like this . . . (indistinct) . . . so like this the body is changing in so many ways, but still I'm the same person. This can be practically experienced. Everyone has this understanding: different bodies, but you're still the same person.
So this spiritual identity should be the real concern. Athāto brahma jijñāsā. This should be the real concern of the human society, not this temporary, changing body. The whole human society is presently geared how to satisfy the demands of this temporary body. So we can see practically that this is fruitless. Ultimately we have to give up this body. Ultimately we have to give up our connection with society, with family, with everything. So everything should have its proper place naturally, but the real focus of human life should be on the soul. This is Kṛṣṇa consciousness—not only the soul, but the relationship of the soul with God. So practically speaking, Kṛṣṇa consciousness is a spiritual movement. We're trying to come to the platform, as Prabhupāda has been speaking in class in the mornings about sat-dharma: eternal religion or eternal activity of the soul. Sat means eternal. Here in this material world everything is temporary. By accident you may be born in America or in India or in Japan or in a human form or in a cat form, but it's temporary. But the soul is eternal, and there is also a place, paras tasmāt tu bhāvaḥ anyaḥ (BG 8.20), another place, beyond this material world, which is called the spiritual world. And that place is sanātana, that place is eternal, and Kṛṣṇa also is eternal. So, sat, sat-dharma or eternal occupation of the soul, eternal religion, is that the living entity should be in this place, this eternal place where there's no change of body—that you have to take a body and then give it up, and then according to your work, take another body and then give it up, revolve in the cycle of birth and death unnecessarily. Go to the sanātana atmosphere, and there the sanātana Lord is there, and there the soul is in its natural environment, and the exchange of love that takes place in this spiritual world, this is sat-dharma.