Prabhupāda: What is the purport? Read.
Śrutakīrti: "The duration of the material universe is limited. It is manifested in cycles of kalpas. A kalpa is a day of Brahmā and one day of Brahmā consists of a thousand cycles of four yugas or ages, Satya, Tretā, Dvāpara and Kali. A cycle of Satya is characterized by virtue, wisdom and religion, there being practically no ignorance and vice, and the yuga lasts one million, seven hundred and twenty-eight thousand years. In the Tretā-yuga vice is introduced and this yuga lasts 1,296,000 years. In the Dvāpara-yuga there is an even greater decline in virtue and religion, vice increasing, and the yuga lasts 864,000 years. And finally in Kali-yuga, the yuga we have now been experiencing over the past five thousand years, there is an abundance of strife, ignorance, irreligion and vice, true virtue being practically non-existent, and this yuga lasts 432,000 years. In Kali-yuga vice increases to such a point that at the termination of the yuga, the Supreme Lord Himself appears as the Kalki avatāra, vanquishes the demons, saves His devotees and commences another Satya-yuga. Then the process is set rolling again. These four yugas, rotating a thousand times, compromise one day of Brahmā, the creator god, and the same number compromise one night. Brahmā lives one hundred of such years and then dies. These hundred years, by Earth calculations total to 311,000,040,000,000 Earth years. By these calculations, a life of Brahmā seems fantastic and interminable, but from the point, from the viewpoint of eternity, it is as brief as a lightning flash. In the Causal Ocean, there are innumerable Brahmās, rising and disappearing like bubbles in the Atlantic. Brahmā and his creation are all part of the material universe, and therefore they are in constant flux. In the material universe, not even Brahmā is free from the process of birth, disease, old age and death. Brahmā, however, is directly engaged in the service of the Supreme Lord in the management of this universe. Therefore he at once attains liberation. Elevated sannyāsīs are promoted to Brahmā's particular planet, Brahmaloka, which is the highest planet in the material universe, and which survives all the heavenly planets in the upper strata of the planetary system. But in due course, Brahmā, and all inhabitants of Brahmaloka are subject to death, according to the law of material nature."
Prabhupāda: In the higher planetary system also, the four rules, birth, death, old age and disease, they are also there. The life is long duration. But the miserable conditions of, or living conditions, that one must die, that is there also. Simply if you go to Kṛṣṇa's planet, you haven't got to die. Ābrahma-bhuvanāl lokāḥ punar āvartino 'rjuna (BG 8.16). Ābrahma-bhuvanāl lokāḥ punar āvartino 'rjuna.
