But you have to change this body. Tatha dehantara-praptih. We are eternal. Na jayate na mriyate va kadacit. The soul does not take birth; neither it dies. We simply change body. Tatha dehantara-praptih. Just like we are changing our body. In mother's womb we had a small body. It grows, and we come out. Again it grows. Grows...It is not actually growing, it is changing. The child is changing his body to baby, the baby is changing his body to boy, and the boy is changing his body to youthhood. Then...in this way you are changing body. That you have got experience. You had a child's body--you remember. Or you had a boy's body--you remember. But the body is no longer existing. But you are existing. Therefore the conclusion is that when this body will be no more fit for existing we shall have to accept another body. This is called tatha dehantara-praptih. So we have to change. That is nature's law. The soul is immortal. Na jayate na mriyate va kadacit na hanyate hanyamane sarire [Bg. 2.20]. The soul is not finished, simply a particular type of body being finished, no. The people do not know it. And because they are simply engaged in sinful activities, their brain has become so dull that they cannot understand this simple truth that as you are changing body in this life therefore you will change this body to another life. This is very simple truth. But at the advancement of material civilization, we have become so dull and rascal that we cannot understand it.

[Srila Prabhupada from a Srimad-Bhagavatam Lecture,Melbourne, May 19, 1975]