Atheists generally follow the Bauddha philosophical conclusion that at death everything is finished. Hiraṇyakaśipu, being an atheist, thought this way. Because Lord Viṣṇu was not visible to him, he thought that the Lord was dead. Even today, many people follow the philosophy that God is dead. But God is never dead. Even the living entity, who is part of God, never dies. Na jāyate mriyate vā kadācit: "For the soul there is never birth or death." This is the statement of Bhagavad-gītā (BG 2.20). Even the ordinary living entity never takes birth or dies. What then is to be said of the Supreme Personality of Godhead, who is the chief of all living entities? He certainly never takes birth or dies. Ajo'pi sann avyayātmā (BG 4.6). Both the Lord and the living entity exist as unborn and inexhaustible personalities. Thus Hiraṇyakaśipu's conclusion that Viṣṇu was dead was wrong.
As indicated by the words yato nāvartate pumān, there is certainly a spiritual kingdom, and if the living entity goes there, he never returns to this material world. This is also confirmed in Bhagavad-gītā (BG 4.9): tyaktvā dehaṁ punar janma naiti mām eti so'rjuna. Materially speaking, every living entity dies; death is inevitable. But those who are karmīs, jñānīs and yogīs return to this material world after death, whereas bhaktas do not. Of course, if a bhakta is not completely perfect he takes birth in the material world again, but in a very exalted position, either in a rich family or a family of the purest brāhmaṇas (śucīnām śrīmatāṁ gehe (BG 6.41)), just to finish his development in spiritual consciousness. Those who have completed the course of Kṛṣṇa consciousness and are free from material desire return to the abode of the Supreme Personality of Godhead (yad gatvā na nivartante tad dhāma paramaṁ mama (BG 15.6)). Here the same fact is stated: yato nāvartate pumān. Any person who goes back home, back to Godhead, does not return to this material world.