Bhagavad Gita: Chapter 15, Verse 6

न तद्भासयते सूर्यो न शशाङ्को न पावक: |
यद्गत्वा न निवर्तन्ते तद्धाम परमं मम || 6||

na tad bhāsayate sūryo na śhaśhāṅko na pāvakaḥ
yad gatvā na nivartante tad dhāma paramaṁ mama

naneither; tatthat; bhāsayateillumine; sūryaḥthe sun; nanor; śhaśhāṅkaḥthe moon; nanor; pāvakaḥfire; yatwhere; gatvāhaving gone; nanever; nivartantethey return; tatthat; dhāmaAbode; paramamsupreme; mamaMine


BG 15.6: Neither the sun nor the moon, nor fire can illumine that Supreme Abode of Mine. Having gone There, one does not return to this material world again.


Here, Shree Krishna gives a brief idea of the nature of the divine realm.  The sun, moon, and fire are not required to illuminate this Spiritual Abode as it is naturally self-luminous.  While the material realm is made from the material energy, Maya, the divine realm is made from the spiritual energy, Yogmaya.  It is transcendental to the dualities and defects of material nature, and is perfect in every way.  It is sat-chit-ānand, i.e. full of eternality, knowledge, and bliss. 

That divine realm consists of a spiritual sky, called Paravyom, which contains numerous Abodes full of godly opulence and splendors.  All the eternal forms of God, such as Krishna, Ram, Narayan, etc. have Their own Abodes in that spiritual sky, where They reside eternally with Their devotees and engage in divine Pastimes (Leelas).  Brahma states in his prayers to Shree Krishna: 

goloka-nāmni nija-dhāmni tale cha tasya

devī maheśha-hari-dhāmasu teṣhu teṣhu

te te prabhāva-nichayā vihitāśh cha yena

govindam ādi-puruṣhaṁ tam ahaṁ bhajāmi  

(Brahma Samhitā verse 43)

“In the spiritual sky is Golok, the personal Abode of Shree Krishna.  That spiritual sky also contains the Abodes of Narayan, Shiv, Durga, etc.  I adore Supreme Divine Personality Lord Krishna, by the majesty of whose opulence, this is possible.”  About Golok, the divine Abode of Shree Krishna, Brahma further says: 


tābhir ya eva nija-rūpatayā kalābhiḥ

goloka eva nivasaty akhilātma-bhūto

govindam ādi-puruṣhaṁ tam ahaṁ bhajāmi  

(Brahma Samhitā verse 37)

“I worship Govind, the Supreme Lord, who resides in Golok with the expansion of His own form, Radha.  Their eternal Associates are the sakhis, who are enlivened by the ever-blissful spiritual energy and are the embodiments of sixty-four artistic abilities.”  The devotees who attain God and go to His supreme Abode participate in His divine Pastimes that are imbued with the perfection of the spiritual energy.  Shree Krishna assures Arjun that those souls who go there cross the samsara of birth and death.