薄伽梵歌 8.17

昼意味着宇宙的演化、投射或显现。夜意味着宇宙的消融或普拉拉亚（Pralaya）。诸世界受时间限制或制约，因此它们会再次回归。梵天界（Brahmaloka 或 Satyaloka）也是无常的，尽管它持续一千个时代。当四大宇迦循环一千次时，构成梵天的一昼；当同样数量的宇迦再次过去时，构成一夜。那些能洞察并经历梵天昼夜的人，才能真正知晓何为昼夜。《太阳悉檀多》（Suryasiddhanta）也提及同样的时间划分，一个摩诃宇迦（Mahayuga）由四个宇迦组成，共计4,320,000年，一千个这样的摩诃宇迦构成梵天的一昼，同样长度构成一夜。在宇宙普拉拉亚（消融）期间，世界被吸收到无显（Avyakta）或未显化（Unmanifested）或根本自性（Mulaprakriti）中。正如树木以潜藏状态存在于种子中，整个宇宙在普拉拉亚期间也以种子形式潜藏于根本自性中。这是梵天之夜，是宇宙之夜。在摩诃劫（Mahakalpa，演化）开始时，世界再次被投射出来。宇宙黎明或宇宙之日随之而来。这种宇宙昼夜（演化与消融）的永恒韵律在宏观宇宙中得以维持。在这永恒循环的宇宙昼夜之轮下，没有任何事物能永恒存在。这就是为何《奥义书》的先知、古代圣贤们，生活在超越宇宙昼夜的超验至高存在、不朽的自我、不灭的普鲁沙（Purusha）、生命的终极目标、人类的最高归宿之中。正如被炒过的种子难以发芽，那些已证得不朽梵、绝对者、永恒者的人，也无法回到这个充满悲伤、痛苦和苦难的世界。他们不知昼夜，他们与绝对存在合一。显化与未显化皆居于梵中。梵超越显化与未显化。当世界和身体被摧毁时，梵并未被摧毁。波浪涌起又消退，但海洋不受影响。同样，诸世界生起又消退，但作为万物之源、根本自性之源的梵，始终不受影响。正如饰品由黄金制成，熔化后又回归黄金，所有世界也皆由梵中生出，又回归梵。黄金绝不受其制成的各种形式的影响。同样，梵也丝毫不受世界和众生身体的投射与毁灭（消融）的影响。它始终如其所是。

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.