In the Bhagavad-gītā you'll find that the living entity never is born, neither never dies. Na hanyamāne hanyate, hanyamāne śarīre. Then, "I see that he is dying." Oh, that is dying not; that is his finishing his this present body. The example is given, vāsāṁsi jīrṇāni yathā vihāya (BG 2.22).
Just like one person changes his dress, similarly, when this dress, the present body, is unworkable . . .
Just like one man cannot see. What do you mean by "cannot see"? When the power of vision is no longer working or the spectacle is broken, therefore he cannot see. Similarly, when the all the senses will be broken or cannot work . . . just like eye cannot . . . the eyes cannot work, therefore it is blind, similarly, the hand cannot work, the leg cannot work, the tongue cannot work, because at the last stage when this mechanical arrangement of this body will stop to function, that is called death.
That you try to understand, that as . . . because I cannot see, it does not mean I am dead. Similarly, because these senses of the body cannot function does not mean that I am dead. It is to be understood with little intelligence and with cool head.
So Prahlāda Mahārāja, a great devotee, he's in the line of disciplic succession. He's considered one of the great ācāryas, an authority, ācārya. And who is ācārya? Ācārya means one who knows the intricacies of Vedic knowledge, and he personally behaves in terms of that knowledge and teaches his disciple in terms of that knowledge.