Bhagavad Gita - Chapter 8 - Shloka (Verse) 17

व्याख्या--सहस्रयुगपर्यन्तम् ৷৷. तेऽहोरात्रविदो जनाः --सत्य, त्रेता, द्वापर और कलि--मृत्युलोकके इन चार युगोंको एक चतुर्युगी कहते हैं। ऐसी एक हजार चतुर्युगी बीतनेपर ब्रह्माजीका एक दिन होता है और एक हजार चतुर्युगी बीतनेपर ब्रह्माजीकी एक रात होती है (टिप्पणी प0 470)। दिन-रातकी इसी गणनाके अनुसार सौ वर्षोंकी ब्रह्माजीकी आयु होती है। ब्रह्माजीकी आयुके सौ वर्ष बीतनेपर ब्रह्माजी परमात्मामें लीन हो जाते हैं और उनका ब्रह्मलोक भी प्रकृतिमें लीन हो जाता है तथा प्रकृति परमात्मामें लीन हो जाती है।
कितनी ही बड़ी आयु क्यों न हो, वह भी कालकी अवधिवाली ही है। ऊँचे-से-ऊँचे कहे जानेवाले जो भोग हैं, वे भी संयोगजन्य होनेसे दुःखोंके ही कारण हैं--'ये हि संस्पर्शजा भोगा दुःखयोनय एव ते' (गीता 5। 22) और कालकी अवधिवाले हैं। केवल भगवान् ही कालातीत हैं। इस प्रकार कालके तत्त्वको जाननेवाले मनुष्य ब्रह्मलोकतकके दिव्य भोगोंको किञ्चिन्मात्र भी महत्त्व नहीं देते।
सम्बन्ध--ब्रह्माजीके दिन और रातको लेकर जो सर्ग और प्रलय होते हैं, उसका वर्णन अब आगेके दो श्लोकोंमें करते हैं।

ब्रह्मलोकसहित समस्त लोक पुनरावर्ती किस कारणसे हैं कालसे परिच्छिन्न हैं इसलिये कालसे परिच्छिन्न कैसे हैं --, ब्रह्मा -- प्रजापति अर्थात् विराट्के एक दिनको एक सहस्रयुगकी अवधिवाला अर्थात् जिसका एक सहस्रयुगमें अन्त हो ऐसा समझते हैं। तथा ब्रह्माकी रात्रिको भी सहस्रयुगकी अवधिवाली अर्थात् दिनके बराबर ही समझते हैं। ऐसा कौन समझते हैं सो कहते हैं -- वे दिन और रातके तत्त्वको जाननेवाले अर्थात् कालके परिमाणको जाननेवाले योगीजन ऐसा जानते हैं। इस प्रकार कालसे परिच्छिन्न होनेके कारण वे सभी लोक पुनरावृत्तिवाले हैं।

He shows the reason for the return of [the worlds] including the realm of Brahma through a question — [starting with] "Brahma".

He establishes that very reason in the next verse with an expectation [of the explanation] — [starting with] "Katham" (How), etc.

Since Prajapati (Brahma) is limited by a lifespan numbered at one hundred [years], composed of parts such as days and nights, months, seasons, solstices, and years as described, the worlds existing within that are also subject to return because they are limited by their respective appropriate times; intending this, he explains — [starting with] "Sahasra" (Thousand), etc.

Having stated the literal meaning, he states the purport — [starting with] "Yataḥ" (Since/Because).

'Worlds including Brahma-loka are returning'—this was stated; he establishes this by the reason that they are 'limited by time'.

"Sahasram yugani" (Thousand yugas) is the 'Paryanta'—limit/end—of which day, that day is "Sahasrayugaparyantam" (Lasting for a thousand yugas). The word 'Yuga' here refers to 'Chaturyuga' (group of four yugas). From the Purana statement: "A thousand Chaturyugas is called a day of Brahma."

The measure of a Chaturyuga is—what is a year for humans, that is a day and night for gods; by such days and nights, in the order of fortnights etc., by twelve thousand years a Chaturyuga is formed. There, four thousand years is Krita Yuga (Satya Yuga), three thousand Treta, two thousand Dvapara, one thousand Kali; eight hundred is the preceding and succeeding twilight (Sandhya) of Krita Yuga; similarly ahead also, in the order of yugas, the order of twilights having the number six hundred, four hundred, and two hundred should be understood.

Ending with a thousand yugas, they know the 'Ahah' (Day) of Brahma—Prajapati—Virat. The night also as 'Sahasrayugantam'—ending with a thousand yugas—they know that (night) as having the same measure as the day. Who know?—he says. Those "Ahoratravidah"—people who know the calculation of time of Brahma's day and night; not those who know the time of human day and night; this is the meaning.

Since thus Prajapati is limited by the life-span of the number one hundred, composed of parts like months, seasons, solstices, and years which are parts of the stated day and night; (therefore) the worlds existing within him are also limited by appropriate time; therefore all worlds including Brahma-loka are returning; this is the intention.

To establish that "Having attained Me there is no return"; to show the Self-power named 'Avyakta' (Unmanifest); He shows dissolution etc.—with "Sahasrayuga" etc.

The word "Sahasra" (Thousand) here denotes 'many'. "Brahma" refers to the Supreme. "That is the night of the Universal Form"—is the Shruti.

The 'Two-Parardha Dissolution' (Mahapralaya) alone is intended here. Because of the statement "From the Unmanifest all manifestations..." (8.18).

And it is stated in the Mahakurma (Purana): "Lasting for many yugas is the night of Mahavishnu; at the beginning of night everything dissolves, and at the beginning of day it is born"—thus. And from the remainder of the sentence "That which in all beings..." (8.20) also.

He states the time limitation of those who are subject to return — with "Sahasra" etc. The word 'Yuga' here is a synonym for Chatur-yuga (the aggregate of four ages). As seen in another Purana: "A thousand Chatur-yugas are said to be a day of Brahma." [Thus,] "Sahasra" means a thousand Chatur-yugas are the paryanta — the termination/end — of which [day]. A thousand Chatur-yugas make Brahma's day,

and the night is also of the same duration; he says this with "Rātrim". Here too, that in which there is the end of a thousand Chatur-yugas is [called] caturyugasahasrāntām. Those famous people who are ahorātravidaḥ (knowers of day and night) know this.

Those people who know the arrangement of day and night created by My resolve (Sankalpa) for beings ranging from humans up to the Four-faced One (Chaturmukha Brahma),

know that the 'day' of Brahma ends after a thousand Chatur-yugas, and that the 'night' is also of the same nature.

(Objection:) "Ascetics, the charitable, the dispassionate, and the forbearing attain a place above the three worlds that is devoid of sorrow" — from such Puranic statements, the superiority of Maharloka and others over the three worlds is understood. If there is no distinction regarding perishability among all of them, how can this special distinction exist? Raising this doubt, and intending that "this distinction is caused by their endurance for many Kalpas," and to show that "in every day of Brahma—who has a lifespan of one hundred years by his own measure—the origin of the three worlds occurs, and in every night the dissolution occurs," He states the measure of Brahma's day and night — with "Sahasra" etc.

Those who know that 'day' of Brahma, of which a thousand Yugas are the paryanta (termination/end), and who know the 'night' which ends in a thousand Yugas through the power of Yoga — they alone are the all-knowing people, the ahorātravidaḥ (knowers of day and night). However, those whose knowledge is limited only to the movements of the moon and sun are not ahorātravidaḥ in that sense, because of their limited vision.

By the word 'Yuga' here, Chatur-yuga is intended, because of the statement in the Vishnu Purana: "A thousand Chatur-yugas are called a day of Brahma." Also, [the word] "Brahmaṇaḥ" (of Brahma) implies the inhabitants of Maharloka and others as well.

There, the method of calculating time is this: What is one year for humans is one day and night for the gods (Devas). With such days and nights, calculating fortnights, months, etc., twelve thousand [divine] years make one Chatur-yuga. And one thousand Chatur-yugas make a day of Brahma. The night is of the exact same duration. With such days and nights, in the order of fortnights, months, etc., one hundred years is the supreme lifespan (Paramāyu) of Brahma.

He explains the collective meaning of the three verses beginning with 'Sahasra' (8.17-19)—with 'Brahmalokaparyantanam' (Of those up to Brahmaloka). To remove the doubt of the stability of Satyaloka etc. established by the independence of Hiranyagarbha etc., he says 'Paramapurushasankalpakritam' (Created by the will of the Supreme Person). For the Lord's independence alone is the cause for the wonderful arrangement of day and night etc. being neither less nor more. And thus it is said: 'Of Time and of Death...' (Mahabharata 5.68.13), 'The Wheel of Time, the Wheel of the World' (Mahabharata 5.68.12) etc. Similarly it is stated elsewhere: 'Then at the end of a thousand Yugas, I shall withdraw the world again; making all beings, moving and unmoving, rest in Me' etc.

And regarding what is in Manava (Manu Smriti): 'That which is a thousand Yugas, indeed the day of Brahma, holy, they know; and the night of the same measure; they are the people who know day and night' (1.73)—there, since the reading is 'Ye' (Who), the connection is in order. But here (in Gita), in the verse 'Sahasra...', the word 'Yat' (Which/That) connects only with the word 'Ahah' (Day); and then for 'Te' (They), the word 'Ye' (Who) is required; and there too, in the connection 'Those who know (that), they are the people who know day and night'—a sentence in the form of praise defining the 'Knower of day and night' without context would be inconsistent with the subject; therefore the connection is 'Those who are people knowing day and night, they know thus'. Thus, one who propounds authoritativeness in the arrangement of Time is to be accepted here; with this intention he says 'Ye manushyadi' (Who... of humans etc.).

The 'knowledge of day and night' being restated should be regarding all (times) as per fame; by that, the equality of even the Four-faced (Brahma) with humans etc. would be indicated; with this intention 'Manushyadi' etc. is said. To remove the delusion that the word 'Brahma' here refers to the Supreme Self, the word 'Chaturmukha' (Four-faced) is used. For the division of day and night restricted to a thousand yugas is famous for him alone; this is the purport.

By the logic 'Injunctions and prohibitions with adjectives apply to the adjective', and since the part 'Those who are people knowing day and night' is restated, the 'knowledge of the limit of a thousand yugas' is alone enjoined here; with this intention 'They know that ending in a thousand chaturyugas' is said. 'Sahasrayugaparyantam'—that whose 'Paryanta' (end) is a thousand yugas. And the word 'Yuga' here refers to Chaturyuga in accordance with other proofs.

'Let there be such an arrangement of day and night for the Four-faced; what is that to the subject?'—the answer to this is the verse 'Avyaktat' (From the Unmanifest - 8.18). He states its meaning—with 'Tatra' (There). This is the intention—The word 'Vyakti' (Manifestation) here is not regarding Mahat etc., because of their origin even before the Four-faced (Brahma). Therefore, it is regarding only what is creatable by the Four-faced. 'Vyajyante' (Are manifested)—thus 'Vyaktayah'. Even there, since there is no dissolution of Satyaloka etc. in every Kalpa, it must be accepted as referring only to objects like body and senses existing inside the three worlds. And their origin is from the body of Brahma alone. And then, the word 'Avyakta' here also does not refer to the Root Unmanifest (Mula-Avyakta), but to the body of Brahma which is their material cause. And the usage of the word 'Avyakta' for the body is explained in the Sutra also: 'But the Subtle, because of fitness' (Brahma Sutra 1.4.2).

The specific cause of such creation and dissolution; and due to its non-destruction, the non-destruction of the stream of creation and dissolution; the avoidance of the contingency of 'arrival of unmerited' and 'loss of merited'; the pervasion of the stated meaning in all Kalpas; and the 'creation as before'—the verse 'Bhutagramah' (Multitude of beings - 8.19) propounds this; with this intention he says 'Sa evayam' (That very this). The word 'Bhuta' here refers to the Knower of the Field (Kshetrajna) qualified by non-sentient matter. That the helplessness which is the cause of being created and destroyed is indeed based on Karma—with this intention 'Karmavashya' (Subject to Karma) is said.

The phrase 'Aharagame' (at the coming of day) should be continued in 'Bhutva' (having become/been born) also; with this intention the connection 'Having been born at the coming of day' is stated. And this propounding of Occasional Dissolution (Naimittika Pralaya) is also an indication (upalakshana) for the Natural Dissolution (Prakrita Pralaya) famous in Shruti etc. That being so, the destruction of Satyaloka is established; for "Worlds up to Brahma-bhuvan" (8.16) was the starting point; with this intention he says "Tatha" (Similarly). Or, the word 'Ratryagama' (Coming of night) itself includes by implication (shakti) the coming of the final night of Brahma also; this is the purport. This is indicated by "At the end of thousand yugas in the form of the end of hundred years." And thus it is remembered elsewhere: "By his own measure, the life-span is considered a hundred years." Similarly, the word 'Aharagama' also includes the first day.

When even elements like Earth etc. dissolve, what to speak of Brahma-loka, Brahma's body, Brahma's egg (universe) etc. which are begun by them—with this intention, the Shruti "Prithivi..." etc. is cited. The unification of the insentient substance in the state of Tamas is indeed heard in the Supreme God alone. Here too, "I am the origin and dissolution of the entire world" (7.6) etc. is indeed said; with this intention "Mayyeva" (In Me alone) is said. "He who creates Brahma first" (Svetasvatara 6.18), "Narayana alone existed, not Brahma not Ishana" (Mahopanishad 1.1)—by this order, the creation of Brahma etc. again, and again his dissolution etc. should also be contemplated.

He shows the utility of propounding such creation and dissolution to the context—with "Evam" (Thus). In all sections on creation and dissolution, this alone should be considered the purport. By "Of the entire distinct from Me," the previously said "I am of the entire..." (7.6) is reminded. And it is said in Mokshadharma also: "And there is no eternal being, moving or unmoving, in the world; except that one Person, Vasudeva, the Eternal" (Mahabharata 12.339.32).

आइन्स्टीन के सापेक्षवाद ने एक रहस्योद्घाटन किया है जो कि अब पश्चिमी देशों में स्वीकृत हो चुका है। इस सिद्धांत के अनुसार देश और काल की कल्पनाएं उन व्यक्तिगत तत्त्वों पर निर्भर करती हैं जो इनके मापदण्ड के नियामक होते हैं। जब मन क्षुब्ध होता है तब समय भार मालूम पड़ता है और मन्दगति से बीत रहा प्रतीत होता है जैसे जब कोई व्यक्ति किसी की व्याकुलता या अत्यन्त उत्सुकता से प्रतीक्षा कर रहा होता है किन्तु उसी व्यक्ति को समय उड़ता हुआ प्रतीत होता है जब वह विश्राम और सुखदायक परिस्थितियों में बैठा हो जहाँ उसका मनोरंजन हो रहा हो। ताश खेलने में मग्न पुरुष को रात कैसे व्यतीत हो गई इसका भान नहीं रहता और उषाकाल की सूर्य की किरणों को खिड़की में से आते देखकर उसे आश्चर्य होता है। मन के प्रतिकूल कार्य करना पड़े अथवा शरीर में पीड़ा हो तो एकएक क्षण युगों के समान जान पड़ता है। निद्रावस्था के एक अखण्ड अनुभव में काल की कोई कल्पना नहीं होती।उपर्युक्त घटनाओं के निरीक्षण से हिन्दू दार्शनिक इस युक्तियुक्त निष्कर्ष पर पहुँचे कि वास्तव में जिसे हम काल कहते हैं वह दो भिन्नभिन्न अनुभवों के मध्य के अन्तराल की गणना है। मन को क्षुब्ध करने वाले अनुभवों की संख्या जितनी ही अधिक होगी समय की गति मन्द अनुभव होगी। एक ही अनुभव यदि दीर्घकाल तक बना रहे तो समय तीव्र गति से व्यतीत होगा। केवल एक ही अनुभव में काल का अनुभव नहीं होता जैसे एक ही बिन्दु पर दूरी की गणना नहीं होती क्योंकि दो बिन्दुओं के मध्य अन्तराल की गणना से ही दूरी नापी जा सकती है। इस सिद्धांत के आधार पर काल की गणना करते हुए पौराणिक कवियों ने जो कहा कि देवताओं की घड़ियों के डायल बड़े होते हैं तो उनका कथन उपयुक्त ही है उपनिषदों में भी आनन्द की मीमांसा की गई है जिसमें एक मानवीय आनन्द को इकाई मानकर ब्रह्माजी तक के देवों को प्राप्त आनन्द की मात्रा की गणना की गई है। र्मत्यलोक से उच्चतर विभिन्न लोकों में आनन्द की मात्रा में वृद्धि उन लोकों में प्राप्त होने वाली मन की शान्ति एवं समता के तारतम्य को दर्शाती है।इस श्लोक में कहा गया है कि ब्रह्माजी का एक दिन एक सहस्र युगों का होता है तथा एक रात्रि भी उतनी ही दीर्घ होती है। युग से तात्पर्य कल्प से है। कालविदों ने जो यह गणना की है वह हमारे 365 दिनों के एक वर्ष की गणना के अनुसार है। चार युगों का एक कल्प होता है और ब्रह्माजी का एक दिन एक सहस्र कल्पों का माना गया है।जैसे व्यष्टि इकाइयाँ होंगी वैसे ही समष्टि होगी। व्यष्टि (एक) मन स्वेच्छा से अपनी सृष्टि की रचना करता है और उसका पोषण भी करता है। तत्पश्चात् उसे नष्ट कर देता है केवल पुनः नई सृष्टि रचने के लिए। सृष्टि और लय का यह निरन्तर कार्य मनुष्य केवल दिन में अर्थात् अपनी जाग्रत्अवस्था में ही करता है। इसी प्रकार यह माना जाता है कि समष्टि मन अर्थात् ब्रह्मा जी इस चराचर सृष्टि की रचना केवल उनकी जाग्रत् अवस्था में करते हैं।

(Objection) "Now, who knows thus that there is return from all worlds? For Brahma and others indeed are heard to be existing for a very long time. How are they themselves subject to return? For if they are subject to return, they too would be possessed of the nature of origin and dissolution?" Anticipating this doubt, He says—"Sahasra" (Thousand) etc. up to "Agama" (Arrival - end of verse 8.19).

Those indeed who are far-sighted, they see the night and day even of Brahma as dissolution and origin. And thus, day by day, those very ones waking up follow their own respective activities; and every night, there is the standing (residence) of those very ones whose vibration has ceased, in the form of potential power only.

Thus in creation and dissolution, there is repeated becoming (existence). Not others and others are created, but those very Jivas. But the distinction is only of the nature of the perception of 'long' and 'quick' caused by Time.

And this limitation exists even for the Prajapatis. And therefore, they too are indeed possessed of the nature of origin and dissolution; this is established.

Suspecting inconsistency of the subsequent section, he says—"Mam prapya" (Having attained Me). "Of those established (in Me)" is the remainder. For that (non-return) was stated merely as a proposition; since the power of the 'Unmanifest' is described here, how is it called 'Atman' (Self)? To this it was said—"Named Unmanifest" (Avyaktakhya).

"Dissolution etc." implies the Self's causality of that. To indicate the absence of "having this as first" (beginning) regarding creation and dissolution, it is stated by transgressing the (order of) Gita.

Here, to refute the perception that the word "Sahasra" denotes "ten hundreds," he says—"Sahasra". This is a synonym for the word "Many" (Bahu), and not the famous meaning (1000).

"Since the famous day and night of Virincha (Brahma) end in a thousand Chaturyugas, how is this (interpretation proper)?" To this he says—"Brahma" (Supreme Brahman). And thus, since the 'Two-Parardha Dissolution' (Mahapralaya) and the 'Primordial Creation' are intended here, what is said is logical.

(Objection) "Now, since the Supreme Brahman is eternal, there are no day and night in Him; so how does this refer to Him?" To this he says—"Sa" (That). "That actionless state is the 'Night' even of the perfect-formed Hari"—this is the meaning. By this, 'Day' is also established.

(Objection) "This would be so if there were proof here for intending the Two-Parardha Dissolution and Primordial Creation?" To this he says—"Dviparardha". Similarly, "Primordial Creation" should also be grasped. For in the intermediate creation and dissolution, there is no origination and destruction of all effects; this is the purport.

And because of the agreement of other scriptures also, it is thus—he says "Uktam cha" (And it is said).

For this reason also it is thus—he says—"Yah" (That which... 8.20). For in intermediate dissolution, there is no destruction of all elements like Akasha etc.; nor is there imperishability of Virincha (Brahma) when the five elements are destroyed; this is the purport.

Why are all worlds, including Brahma-loka, subject to return? Because they are limited by time; thus He says —

"by human calculation, lasting a thousand Yugas" etc. Sahasra-yuga-paryantam — that of which a thousand Yugas, meaning Chatur-yugas, are the paryanta, i.e., the termination or end. "A thousand Chatur-yugas are indeed said to be a day of Brahma," is the Puranic statement.

Those who know such a 'day' of Brahma, the Lord of beings (Prajapati); and similarly, those who know the 'night' as yuga-sahasrāntām — ending after a thousand Chatur-yugas — [are the knowers]. They are the ahorātravidaḥ (knowers of day and night); they alone are the yogis who truly know day and night.

However, those who know [time] merely by the movement of the moon and sun are not ahorātravidaḥ, because they possess limited vision; this is the purport.

(Objection:) Raising the doubt that based on statements like "Those gone to Brahma-loka are liberated along with him" and "They are liberated along with Brahma," they too should indeed be free from return — He states the absence of that [absolute non-return immediately] for them with "Sahasra" etc.

Sahasra-yuga-paryantam — that 'day' of Brahma of which a thousand Chatur-yugas are the paryanta, i.e., the termination/end — those who know that; and those who know the night as yuga-sahasrāntām — of which a thousand Chatur-yugas are the end — are the ahorātravidaḥ (knowers of day and night).

Regarding the calculation of time there: What is a year for humans is a day and night for the gods; with twelve thousand [divine] years calculated by such days and nights, a Chatur-yuga is formed. And that [thousand Chatur-yugas] is a day of Brahma; the night is of the same duration. By the sequence of that calculation, one hundred years is said to be the supreme lifespan (Paramāyu) of Brahma. At the end of that, the attainment of the Imperishable (Akshara) for those liberated along with him happens sequentially (paramparayā).

"Sahasrayugaparyantam"—That day of which thousand yugas are the 'Paryanta' (limit/end), that day is 'Sahasrayugaparyantam'; (they) know it as of Brahma, the Prajapati, the Virat; (they know) the night also as ending in a thousand yugas, of the same measure as the day indeed.

"Who know?"—He says—"Te ahoratravidah"—meaning the people who know the calculation of Time.

Since they are thus limited by Time, therefore the worlds are subject to return.

What happens in the day of Prajapati, and in the night, that is stated—

(Objection:) Why is it said thus: "Up to the realm of Brahma" [there is return]? (Solution:) It is true, because even Brahma is limited by time; this He states with "Sahasra" etc.

Here the word 'Chatuḥ' (four) should be applied [making it Chatur-yuga], because of the statement "A thousand Chatur-yugas are said to be a day of Brahma."

And according to this measure, it is said that dissolution (Laya) occurs at the end of Brahma's Dviparārdha (two halves of his lifespan).

सहस्रयुगपर्यन्तम् ending in a thousand Yugas (ages)? अहः day? यत् which? ब्रह्मणः of Brahma? विदुः know? रात्रिम् the night? युगसहस्रान्ताम् ending in a thousand Yugas (ages)? ते they? अहोरात्रविदः knowers of day and night? जनाः people.Commentary Day means evolution or projection or manifestation of the universe. Night means involution of the universe or Pralaya. The worlds are limited or conditioned in time. Therefore they return again. The world of Brahma (Brahmaloka or Sattyaloka) is also transient? although it lasts for a thousand ages. When the four great Yugas have gone round a thousan times? it make a daytime of Brahma and when an eal number of Yugas pass again it makes a night. Those who can see and live through the day and night of Brahma can really know what is a day and what is a night.The Suryasiddhanta speaks of the same division of time.According to it YearsKaliyuga (with its Sandhya andSandhyamsa) consists of 432?000Dvapara Yuga (do) 864?000Tretayuga (do) 1?296?000Kritayuga (do) 1?728?000Thus a Mahayuga consisting ofthese four Yugas comprises 4?320?00071 such Mahayugas with an additionalSandhya? at the close of 1?728?000years make one Manvantara of 308?448?00014 such Manvantaras with anotherSandhya? at the close of 1?728?000years constitute one Kalpa of 4?320?000?000Two Kalpas make a day and nightof Brahma of 8?640?000?000360 such days and nights make oneyear of Brahma consisting of 3?110?400?000?000100 such years constituteHis lifetime of 311?040?000?000?000The world is absorbed in the Avyakta or the Unmanifested or Mulaprakriti during the cosmic Pralaya (involution of the world). Just as the tree remains in a latent state in the seed? so also this whole universe remains in a latent state in a seedform in the Mulaprakriti during Pralaya. This is the night of Brahma. This is the cosmic night. Again the world is projected at the beginning of the Mahakalpa (evolution). There comes the cosmic dawn or cosmic day. This eternal rhythm of cosmic day and night (evolution and involution) is kept up in the macrocosm.Nothing that comes under this everrevolving wheel of cosmic day and night lasts for ever. That is the reason why the seers of the Upanishads? the sages of yore? lived in the transcendental Supreme being? the imperishable Self? the indestructible Purusha? the supreme goal of life? the highest end of man? which is beyond the cosmic day and night. Just as the seeds that are fried can hardly germinate? so also those who have attained to the imperishable Brahman? the Absolute? the Eternal? cannot return to this world of sorrow? pain and misery. They know neither day nor night. They are one with Existence Absolute.The manifested and the unmanifested dwell in Brahman. Brahman is beyond the manifested and the unmanifested. When the world and the body are destroyed Brahman is not destroyed. The waves come out and subside? but the ocean remains unaffected. So also the worlds come and subside? but Brahman the source of everything? the source of Mulaprakriti? ever remains unaffected. Just as ornaments come out of gold and then go back to gold when they are melted? so also all the worlds come out of Brahman and go back to Brahman. Gold is in no way affected by the various forms such as earning? bracelets? anklets? etc.? that have been made of it. Even so Brahman is not in the least affected by the projection and destruction (dissolution) of the worlds and the bodies of beings. It remains always as It is.

Viduh, they know; that ahah, day; brahmanah, of Brahma, of Prajapati, of Virat; yat, which; sahasra-yuga-paryantam, ends in a thousand yugas; and also the ratirm, night; yuga-sahasra-antam, which ends in a thousand yugas, having the same duration as the day. Who knows (these)? In reply the Lord says: Te, they; janah, poeple; ahoratra-vidah, who are the knowers of what day and night are, i.e. the people who know the measurement of time. Since the worlds are thus delimited by time, therefore they are subject to return.
What happens during the day and the night of Prajapati is being stated:

These men who know the order of the day and night as established by My will in regard to all beings, beginning with man and ending with Brahma - they understand that what forms Brahma's day is a unit comprising in it a thousand periods of four Yugas (Catur-yugas) and anight is a unit of eal duration.