paras tasmāt tu bhāvo ’nyo
’vyakto ’vyaktāt sanātanaḥ
yaḥ sa sarveṣu bhūteṣu
naśyatsu na vinaśyati

Translation of Bhagavad Gita 8.20

Yet there is another unmanifest nature, which is eternal and is transcendental to this manifested and unmanifested matter. It is supreme and is never annihilated. When all in this world is annihilated, that part remains as it is.

Commentary by Sri A.C. Bhaktivedanta Swami Prabhupada of Gaudiya Sampradaya:

rishna’s superior, spiritual energy is transcendental and eternal. It is beyond all the changes of material nature, which is manifest and annihilated during the days and nights of Brahma. Krishna’s superior energy is completely opposite in quality to material nature. Superior and inferior nature are explained in the Seventh Chapter.

Commentary by Sri Vishvanatha Chakravarthi Thakur of Gaudiya Sampradaya:

Superior to that state of dissolution, to the Hiranyagarbha or Brahma which has been described (parah tasmat avyaktat), is another state,  the cause  of Hiranyagarbha, which is indeed unmanifest (avyakta), and without beginning (sanatanah).

Commentary by Sri Ramanuja of Sri Sampradaya:

8.20 – 8.21 Superior, as an object of human end, to this unmanifest (Avyakta), which is inanimate Prakrti, there is another state of being, of a kind different from this, but also called Avyakta. It has only knowledge-form and is also unmanifest. It is the self, Atman. It is unmanifest because It cannot be apprehended by any means of knowledge (Pramanas). The meaning is that Its nature is unique and that It can be known only to Itself. That is, It can be understood only vaguely in the ordinary ways of knowing. It is eternal, namely, ever-enduring, because It is not subject to origination and annihilation. In texts like ‘For those who meditate on the imperishable, undefinable, the unmanifest’ (12.3) and ‘The imperishable is called the unchanging’ (15.16) — that being the self. It has been called the unmanifest (Avyakta) and imperishable (Aksara); when all material elements like ether, etc., with their causes and effects are annihilated, the self is not annihilated in spite of It being found alone with all the elements. [The elements are what constitute the bodies of beings.] The knowers of the Vedas declare It as the highest end. The meaning is that the imperishable entity which has been denoted by the term ‘highest goal’ in the passage, ‘Whosoever abandons the body and departs (in the manner described) reaches the highest state (Dhama)’ (8.13), is the self (Atman) abiding in Its essential nature free from the contact with the Prakrti. This self, which abides thus in Its essential nature, by attaining which It does not return, — this is My ‘highest abode,’ i.e., is the highest object of My control. The inanimate Prakrti is one object of My control. The animate Prakrti associated with this inanimate Prakrti is the second object of My control. The pristine nature of the freed self, free from contact with inanimate matter, is the highest object of My rule. Such is the meaning. This state is also one of non-return to Samsara. Or the term ‘dhama’ may signify ‘luminosity’. And luminosity connotes knowledge. The essential nature of the freed self is boundless knowledge, or supreme light, which stands in contrast to the shrunken knowledge of the self, when involved in Prakrti. [The description given above is that of Kaivalya, the state of self-luminous existence as the pure self]. Sri Krsna now teaches that the object of attainment for the Jnanin, is totally different from this:

Commentary by Sri Sridhara Swami of Rudra Sampradaya:

After completing the expose on the impermanence of all material worlds, Lord Krishna elucidates in this verse and the next on the eternal nature of the spiritual worlds which exist beyond avyakta the unmanifest and which is never destroyed when all the material worlds perish. Beyond the avyakta is another superior nature, unmanifest which is the cause of prakriti, the material substratum pervading existence, and which exists as the cause of all things in the moving and non-moving universes. This superior unmanifest is beyond the perception of the senses and without a beginning and it never ceases to exist even when all the worlds and all created beings, which are merely causes and effects, inevitably perish.

Commentary by Sri Madhvacharya of Brahma Sampradaya:

Sri Madhvacharya did not comment on this sloka.

Commentary by Sri Keshava Kashmiri of Kumara Sampradaya:

The ultimate substance of the form of the atma is completely distinct from prakriti or the material substrtatum pervading existence and is without birth and death. Thus it better then even the Cosmic Egg from where if one surmounts it there is also no return to material existence. This Lord Krishna is indicating in this verse and the next by the words paras tasmat meaning superior to that. His state is superior because He is totally separate from avyakta the unmanifest that emantes from Brahma and is invariably connected to prakriti or the material substratum pervading physical existence and the cause of the myriad of multitudes of variegated created beings alluded to in the previous verse. Yet Lord Krishna is revealing that there is another superior avyakta which is different, being eternal and full of consciousness which never perishes and is imperceptible by any means and measure of proof except by the evidence revealed in the Vedic scriptures. This superior avyakta coming from Him is never subject to destruction even when all the worlds and universes along with all movable and immovable beings are destroyed.

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.

Commentary by Sri Adi Shankaracharya of Advaita Sampradaya:

8.20 He is parah, distinct, different;-From what?-tasmat, from that aforesaid (Unmanifested). The word tu, but, is meant for showing the distinction of the Immutable that is going to be spoken of from the Unmanifested. He is bhavah, the Reality, the supreme Brahman called the Immutable. Even though different, there is the possibility of similarlity of characteristics. Hence, for obviating this the Lord says: anyah, the other, of a different characteristic, and He is the Immutable which is beyond the range of the organs. It has been said that He is distinct from that. From what, again is He distinct? Avyaktat, from the Unmaifested spoken of earlier, which is the seed of the multitude of beings, and which is characterized as ignorance (avidya) [Ast. adds, ‘anyah vilaksanah, bhavah ityabhiprayah: The meaning is that the Reality is different and distinct (form that Unmanifested).-Tr.] He is sanatnah, eternal. Bhavah, the Reality; yah sah, who is such; na, does not; vinasyati, get destroyed; when sarvesu bhutesu, all beings, beginning from Brahma; nasyatsu, get destroyed.

Commentary by Sri Abhinavagupta of Kaula Tantra Sampradaya:

8.20 See Comment under 8.22

Sanskrit Shloka Without Transliteration Marks:

paras tasmat tu bhavo ’nyo
’vyakto ’vyaktat sanatanah
yah sa sarvesu bhutesu
nasyatsu na vinasyati

Sanskrit to English Word for Word Meanings:

paraḥ — transcendental; tasmāt — to that; tu — but; bhāvaḥ — nature; anyaḥ — another; avyaktaḥ — unmanifest; avyaktāt — to the unmanifest; sanātanaḥ — eternal; yaḥ saḥ — that which; sarveṣu — all; bhūteṣu — manifestation; naśyatsu — being annihilated; na — never; vinaśyati — is annihilated.