SB 6.15.3
yatha prayanti samyanti
sroto-vegena balukah
samyujyante viyujyante
tatha kalena dehinah
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
O King, as small particles of sand sometimes come together and are sometimes separated due to the force of the waves, the living entities who have accepted material bodies sometimes come together and are sometimes separated by the force of time.
Purport by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
The misunderstanding of the conditioned soul is the bodily conception of life. The body is material, but within the body is the soul. This is spiritual understanding. Unfortunately, one who is in ignorance, under the spell of material illusion, accepts the body to be the self. He cannot understand that the body is matter. Like small particles of sand, bodies come together and are separated by the force of time, and people falsely lament for unification and separation. Unless one knows this, there is no question of happiness. Therefore in Bhagavad-gita (2.13) this is the first instruction given by the Lord:
dehino ’smin yatha dehe
kaumaram yauvanam jara
tatha dehantara-praptir
dhiras tatra na muhyati
“As the embodied soul continually passes, in this body, from boyhood to youth to old age, the soul similarly passes into another body at death. The self-realized soul is not bewildered by such a change.” We are not the body; we are spiritual beings trapped in the body. Our real interest lies in understanding this simple fact. Then we can make further spiritual progress. Otherwise, if we remain in the bodily conception of life, our miserable material existence will continue forever. Political adjustments, social welfare work, medical assistance and the other programs we have manufactured for peace and happiness will never endure. We shall have to undergo the sufferings of material life one after another. Therefore material life is said to be duhkhalayam asasvatam; it is a reservoir of miserable conditions.