That is the aim of human life. How to become immortal. How... Not to become, we are immortal. Just like a person, he's diseased, attacked by fever. Fever is not his natural condition, but somehow or other, he has got fever. Similarly, we are immortal. That will be explained. Na jāyate na mriyate vā. The living entity never takes birth, never dies. Therefore immortal. Immortal means no birth, no death. That is immortal. Whenever there is birth, there is death. If there is no birth, there is no death. That is immortality.
So the whole scheme is Vedic scheme, not otherwise: how to become immortal. You find in Bhagavad-gītā, yad gatvā na nivartante tad dhāma paramaṁ mama (BG 15.6). In many places, the śāstra only aims at.