Bhagavad-Gita: Chapter 8, Verse 19

Rudra Vaisnava Sampradaya:

Visnuswami

Sridhara Swami's Commentary

Here Lord Krishna refutes any conjecture that there is permanent destruction of the living beings at any time or that as such they may not receive the exact measure of merits and demerits from their karma or reactions to past actions. This He is revealing by showing that there is an unbroken cycle of creation and dissolution manifesting each day of the 36,000 days of Brahma's 100 year life. This is being shown to infuse a spirit of dispassion for any individuals singular life span. So Lord Krishna explains that all those myriad of unlimited hosts of created beings from all species of life, moving and stationary, walking, crawling, flying, swimming which existed as life forms before dissolution; each and every one of them fully accounted for are created again at Brahma's awakening and only those are manifested and pick up the existence that they were destined to accept from the previous existence according to the stringent laws of karma. So every 8 billion 640 years for each of Brahma's 36,000 days creation and dissolution is perpetually enacted. It is not possible for any manifestation unaccounted for to appear in this matrix as all the hosts of variegated jivas or living entities are all controlled, regulated and processed by the precise maxim of time and individual karma previous existences.

Brahma Vaisnava Sampradaya:

Madhvacarya
There is no commentary for this verse.

Sri Vaisnava Sampradaya:

Ramanuja

Ramanuja's Commentary

Those who understand the succession of Brahma's day and night as established by the Supreme Lord Krishna applicable for all created beings from human up to the highest material being know that the duration of Brahma's day is 4 billion 320 million years and an equal duration is his night. At the dawning of Brahma's day all beings and things in the threefold regions of material existence along with their bodies and senses, objects of enjoyment and locations of enjoyment all in a subtle form issue out of an avyakta or unmanifest state emanting Brahma's subtle body. When Brahma's night draws nigh all that issued out are all once again reabsorbed into that avyakta state of his subtle body. The exact same groups and species of variegated beings adhere to the stringent law of karma or the reactions to previous actions are bound in the material existence and come and go. Appearing in Brahma's day and vanishing in his night again and again perpetually.

One year of Brahma equals 26 trillion, 438 billion and 400 million years. When the duration of Brahma's life which is 100 of such years ends. Then immeadiately all systems of all material worlds in existence, operating in tandem or at random up to Brahma's own planet and even Brahma himself are ended and dissolve into the infinite. This dissolution has an order as confirmed in the Subala Upanisad beginning: Prithivy apsu praliyate, apas tejas liyante meaning Earth is devolved into water, water is devolved into fire. Fire is devolved into air etc. air is devolved into ether, ether is devolved into the cosmos, the cosmos devolves into avyakta the unmanifest, the unmanifest devolves into the aksara the imperishable, the imperishable devolves into tamas or darkness and the darkness merges finally back into the Supreme Being. Thus all things except the Supreme Lord are regulated and controlled by time. All things without exception owe their existence to the Supreme Lord Krishna, deriving their inception from Him and concluding their absorption in Him. In the material worlds there is absolutely no alternative to the cycle of birth and death. Thus at the end of life the forced relinquishing of material wealth and opulence for those who wasted there lives to obtain it is inevitable. But for those who instead used their precious human life to attain the Supreme Lord Krishna, having Him as there sole refuge and goal; for them rebirth is not even to be considered as they are automatically liberated from samsara the perpetual cycle of birth and death. Next will be shown that there is also no rebirth for those who have achieved atma tattva or realisation of the soul.

Kumara Vaisnava Sampradaya:

Nimbaditya

Kesava Kasmiri's Commentary

A doubt may arise that any action performed by those absorbed may be destroyed and later when they reappear they may have to perform entirely new actions. Lord Krishna refutes this doubt and evokes dispassion by inferring enough pondering over the 36,000 cycles of dissolution and creation which transpire during Brahma's lifetime and in which contains 43 million 200 thousand births and deaths for a human being based on a 100 year life span. Lord Krishna specifically clarifies that all movable and immovable living entities that existed on the previous day of Brahma are all manifested again and again as variegated and diverse species such as demigod, human, animal, bird, fish etc., all in precise accordance with the inviolable laws of karma or the subsequent reactions to previous actions. Then again at the beginning of the night of Brahma all are dissolved again under the compulsion of his nature and are absorbed back into the unmanifest which is Brahma's subtle body. The Vedic scriptures proclaim: The creation of the sun, the moon, the Earth, the sky are all exactly as they were before. Then after 36,000 times of creation and dissolution Brahma's life span is ended. At this time all beings movable and immovable all planetary systems and universes, even Brahma and his planet of Maharloka are all dissolved into the ultimate unmanifest starting from the Earth each of the worlds dissolve and are absorbed into the Supreme Being. The Subala Upanisad states: Earth devolves into water, water devolves into fire, fire devolves into air, air devolves into ether and so forth up to the cosmos which devolves into the avyakta or unmanifest, the avyakta into the akshara or the indestructible, the akshara into tamas or darkness and the tamas into the Supreme Lord Krishna, within everything merges. Thus it is confirmed that except for the eternal spiritual worlds of the Supreme Lord Krishna, all beings and the entire material creation consisting of trillions of universes are subject to incessant creation and dissolution periodically.

Although this process irrevocably applies to all beings indiscriminately there is one exception. In the case of Lord Krishna's initiated devotees in authorised parampara or disciplic succession from any one of the four bonafide sampradaya's as confirmed in Vedic scriptures being Brahma Sampradaya, Sri Sampradaya, Rudra Sampradaya and Kumara Sampradaya; they alone are exempt from rebirth again for once attaining Lord Krishna there is no question of any one of them ever having to take birth in the material worlds again for they are automatically promoted to the eternal spiritual worlds to associate with Him.