In the material world the brahmajyoti, the Lord's spiritual effulgence, is covered by the mahat-tattva (material elements); therefore in this material world we require the assistance of sun, moon, electricity, etc, for light.

Srila Prabhupada - "The Supersoul, the Supreme Personality of Godhead, is the source of light in all luminous objects like the sun, moon and stars. 

In the Vedic literature we find that in the spiritual kingdom there is no need of sun or moon, because the effulgence of the Supreme Lord is there. 

In the material world that brahma-jyotir, the Lord's spiritual effulgence, is covered by the mahat-tattva, the material elements; therefore in this material world we require the assistance of sun, moon, electricity, etc., for light. But in the spiritual world there is no need of such things. 

It is clearly stated in the Vedic literature that because of His luminous effulgence, everything is illuminated. It is clear, therefore, that His situation is not in the material world. He is situated in the spiritual world, which is far, far away in the spiritual sky. 

That is also confirmed in the Vedic literature. Āditya—varṇaṁ tamasaḥ parastāt (Śvetāśvatara Upaniṣad 3.8). He is just like the sun, eternally luminous, but He is far, far beyond the darkness of this material world." (BG 13.18, Purport)

Srila Prabhupada - "Devotional service to the Lord is very simple: one should always engage in the service of the Lord, should eat the remnants of foodstuffs offered to the Deity, smell the flowers offered to the lotus feet of the Lord, see the places where the Lord had His transcendental pastimes, read of the different activities of the Lord, His reciprocation of love with His devotees, chant always the transcendental vibration Hare Kṛṣṇa, Hare Kṛṣṇa, Kṛṣṇa Kṛṣṇa, Hare Hare/ Hare Rāma, Hare Rāma, Rāma Rāma, Hare Hare, and observe the fasting days commemorating the appearances and disappearances of the Lord and His devotees. By following such a process one becomes completely detached from all material activities. One who can thus situate himself in the brahma-jyotir or the different varieties of the Brahman conception is equal to the Supreme Personality of Godhead in quality." (BG 14.27, Purport)

Srila Prabhupada - "The spiritual world, the abode of the Supreme Personality of Godhead, Kṛṣṇa—which is known as Kṛṣṇaloka, Goloka Vṛndāvana is described here. In the spiritual sky there is no need of sunshine, moonshine, fire or electricity, because all the planets are self-luminous. We have only one planet in this universe, the sun, which is self-luminous, but all the planets in the spiritual sky are self-luminous. The shining effulgence of all those planets (called Vaikuṇṭhas) constitutes the shining sky known as the brahma-jyotir. Actually, the effulgence is emanating from the planet of Kṛṣṇa, Goloka Vṛndāvana. Part of that shining effulgence is covered by the mahat-tattva, the material world. Other than this, the major portion of that shining sky is full of spiritual planets, which are called Vaikuṇṭhas, chief of which is Goloka Vṛndāvana." (BG 15.6, Purport)

Srila Prabhupada - "The Supreme Lord, in His localized aspect of Paramātmā, is also described in the Vedas themselves. The following verse appears in the Vedas (Chāndogya Upaniṣad 8.12.3): tāvad eṣa samprasādo 'smāc charīrāt samutthāya paraṁ jyoti-rūpaṁ sampadya svena rūpeṇābhiniṣpadyate sa uttamaḥ puruṣaḥ. "The Supersoul coming out of the body enters the impersonal brahma-jyotir; then in His form He remains in His spiritual identity. That Supreme is called the Supreme Personality." This means that the Supreme Personality is exhibiting and diffusing His spiritual effulgence, which is the ultimate illumination. That Supreme Personality also has a localized aspect as Paramātmā. By incarnating Himself as the son of Satyavatī and Parāśara, He explains the Vedic knowledge as Vyāsadeva." (BG 15.18, Purport)

Srila Prabhupada - "In the Bhagavad-gītā it is said that the brahma-jyotir, or the glowing transcendental effulgence, is resting on Lord Śrī Kṛṣṇa. In other words, the glowing effulgence known as brahma-tejas is nothing but the rays of the Lord, just as the sun rays are rays of the sun disc. So this Brahma weapon also, although materially irresistible, could not surpass the supreme strength of the Lord. The weapon called brahmāstra, released by Aśvatthāmā, was neutralized and foiled by Lord Śrī Kṛṣṇa by His own energy; that is to say, He did not wait for any other's help because He is absolute." (SB 1.8.15, Purport)

Srila Prabhupada - "Because the Lord is the property of the devotees, and the devotees are the property of the Lord reciprocally, the devotees are certainly transcendental to the modes of material nature. That is a natural conclusion. Such unalloyed devotees are distinct from the mixed devotees who approach the Lord for mitigation of miseries and poverty or because of inquisitiveness and speculation. The unalloyed devotees and the Lord are transcendentally attached to one another. For others, the Lord has nothing to reciprocate, and therefore He is called ātmārāma, self-satisfied. Self-satisfied as He is, He is the master of all monists who seek to merge into the existence of the Lord. Such monists merge within the personal effulgence of the Lord called the brahma-jyotir, but the devotees enter into the transcendental pastimes of the Lord, which are never to be misunderstood as material." (SB 1.8.27, Purport)

Srila Prabhupada - "In the Bhagavad-gītā (9.11) the Lord says that only the foolish take Him to be a mere human being. Such foolish men are not aware of His inconceivable energies. By His inconceivable energy He is present in everyone's heart, as the sun is present before everyone all over the world. The Paramātmā feature of the Lord is an expansion of His plenary portions. He expands Himself as Paramātmā in everyone's heart by His inconceivable energy, and He also expands Himself as the glowing effulgence of brahma-jyotir by expansion of His personal glow. It is stated in the Brahma-saṁhitā that the brahma-jyotir is His personal glow. Therefore, there is no difference between Him and His personal glow, brahma-jyotir, or His plenary portions as Paramātmā. Less intelligent persons who are not aware of this fact consider brahma-jyotir and Paramātmā to be different from Śrī Kṛṣṇa. This misconception of duality is completely removed from the mind of Bhīṣmadeva, and he is now satisfied that it is Lord Śrī Kṛṣṇa only who is all in all in everything. This enlightenment is attained by the great mahātmās or devotees, as it is stated in Bhagavad-gītā (7.19) that Vāsudeva is all in all in everything and that there is no existence of anything without Vāsudeva. Vāsudeva, or Lord Śrī Kṛṣṇa, is the original Supreme Person, as now confirmed by Bhīṣmadeva. Since Bhīṣmadeva is one of the twelve mahājanas, or great authorities, both the neophytes and the pure devotees must try to follow in his footsteps. That is the way of the devotional line." (SB 1.9.42, Purport)

Srila Prabhupada - "The worshipable object of Bhīṣmadeva is Lord Śrī Kṛṣṇa as Pārtha-sārathi, and that of the gopīs is the same Kṛṣṇa in Vṛndāvana as the most attractive Śyāmasundara. Sometimes less intelligent scholars make a mistake and think that the Kṛṣṇa of Vṛndāvana and that of the Battle of Kurukṣetra are different personalities. But for Bhīṣmadeva this misconception is completely removed. Even the impersonalist's object of destination is Kṛṣṇa as the impersonal jyoti, and the yogī's destination of Paramātmā is also Kṛṣṇa. Kṛṣṇa is both brahma-jyotir and localized Paramātmā, but brahma-jyotir and Paramātmā are not full representations of Kṛṣṇa. In Kṛṣṇa there are both brahma-jyotir and Paramātmā, but in brahma-jyotir or Paramātmā there is no Kṛṣṇa or sweet relations with Kṛṣṇa. In His personal feature Kṛṣṇa is both Pārtha-sārathi and Śyāmasundara of Vṛndāvana, but in His impersonal feature He is neither in the brahma-jyotir nor in the Paramātmā. Great mahātmās like Bhīṣmadeva realize all these different features of Lord Śrī Kṛṣṇa, and therefore they worship Lord Kṛṣṇa with one-pointed attention, knowing Him as the origin of all features." (SB 1.9.42, Purport)

Srila Prabhupada - "The jñānīs and yogīs enter into the impersonal rays of the Supreme, but the bhaktas enter into the spiritual planets known as the Vaikuṇṭhas. In these spiritual planets the Supreme Lord as Nārāyaṇa predominates, and the healthy, unconditioned living beings live there by rendering loving service to the Lord in the capacity of servant, friend, parents and fiancee. There the unconditioned living beings enjoy life in full freedom with the Lord, whereas the impersonalist jñānīs and yogīs enter into the impersonal glowing effulgence of the Vaikuṇṭha planets. The Vaikuṇṭha planets are all self-illuminating like the sun, and the rays of the Vaikuṇṭha planets are called the brahma-jyotir. The brahma-jyotir is spread unlimitedly, and the material world is but a covered portion of an insignificant part of the same brahma-jyotir. This covering is temporary, and therefore it is a sort of illusion." (SB 1.9.44, Purport)

Srila Prabhupada - "The reason is that I reserve the power of not being exposed to the nondevotees by My mystic curtain. The less intelligent fools are therefore unaware of My eternal form, which is never to be vanquished and is unborn." In the Padma Purāṇa it is said that those who are envious and always angry at the Lord are unfit to know the actual and eternal form of the Lord. In the Bhāgavatam also it is said that the Lord appeared like a thunderbolt to those who were wrestlers. Śiśupāla, at the time of being killed by the Lord, could not see Him as Kṛṣṇa, being dazzled by the glare of the brahma-jyotir. Therefore, the temporary manifestation of the Lord as a thunderbolt to the wrestlers appointed by Kaṁsa, or the glaring appearance of the Lord before Śiśupāla, was relinquished by the Lord, but the Lord as a magician is eternally existent and is never vanquished in any circumstance. Such forms are temporarily shown to the asuras only, and when such exhibitions are withdrawn, the asuras think that the Lord is no more existent, just as the foolish audience thinks the magician to be burnt to ashes or cut to pieces. The conclusion is that the Lord has no material body, and therefore He is never to be killed or changed by His transcendental body." (SB 1.15.35, Purport)

Srila Prabhupada - "Only fools are ungrateful to their benefactors. The Lord, however, does not require benefit from anyone besides Himself because He is full in Himself; still He feels benefited by the unalloyed services of His devotees. The Lord feels grateful to His devotees for such unsophisticated, unconditional service and tries to reciprocate it by rendering service, although the devotee also has no such desire in his heart. The transcendental service of the Lord is itself a transcendental benefit for the devotee, and therefore the devotee has nothing to expect from the Lord. On the assertion of the Vedic aphorism sarvaṁ khalv idaṁ brahma, we can understand that the Lord, by the omnipresent rays of His effulgence, called brahma-jyotir, is all-pervading inside or outside of everything, like the omnipresent material sky, and thus He is also omniscient." (SB 1.16.26-30, Purport)

Srila Prabhupada - "There is some controversy amongst the students on the path of liberation. Such transcendental students are known as impersonalists and devotees of the Lord. The devotee of the Lord worships the transcendental form of the Lord, whereas the impersonalist meditates upon the glaring effulgence, or the bodily rays of the Lord, known as the brahma-jyotir. Here in this verse it is said that Mahārāja Parīkṣit attained the lotus feet of the Lord by instructions in knowledge delivered by the son of Vyāsadeva, Śrīla Śukadeva Gosvāmī. Śukadeva Gosvāmī was also an impersonalist in the beginning, as he himself has admitted in the Bhāgavatam (2.1.9), but later on he was attracted by the transcendental pastimes of the Lord and thus became a devotee. Such devotees with perfect knowledge are called mahā-bhāgavatas, or first-class devotees." (SB 1.18.16, Purport) 

Srila Prabhupada - "The above-mentioned state of affairs is factual on the transcendental plane, but is factually revealed in a transcendentalist's knowledge of the advanced state of pure consciousness. Such transcendentalists are of two types, namely the impersonalists and the devotees. For the impersonalist the ultimate goal or destination is the brahma-jyotir of the spiritual sky, but for the devotees the ultimate goal is the Vaikuṇṭha planets. The devotees experience the above-mentioned state of affairs by attainment of spiritual forms for activity in the transcendental loving service of the Lord. But the impersonalist, because of his neglecting the association of the Lord, does not develop a spiritual body for spiritual activity, but remains a spiritual spark only, merged in the effulgent spiritual rays of the Supreme Personality of Godhead. The Lord is the full-fledged form of eternity, bliss and knowledge, but the formless brahma-jyotir is simply eternity and knowledge. The Vaikuṇṭha planets are also forms of eternity, bliss and knowledge, and therefore the devotees of the Lord, who are admitted into the abode of the Lord, also get bodies of eternity, bliss and knowledge. As such there is no difference between one and another. The Lord's abode, name, fame, entourage, etc., are of the same transcendental quality, and how this transcendental quality differs from the material world is explained herewith in this verse. In the Bhagavad-gītā, three principal subjects have been explained by Lord Śrī Kṛṣṇa, namely karma-yoga, jñāna-yoga and bhakti-yoga, but one can reach the Vaikuṇṭha planets by the practice of bhakti-yoga only. The other two are incompetent in helping one reach the Vaikuṇṭhalokas, although they can, however, conveniently take one to the effulgent brahma-jyotir, as described above." (SB 2.2.17, Purport)

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