The brahmajyoti is described in the Brahma-saṁhitā as the rays emanating from that supreme spiritual planet, Goloka Vṛndāvana, just as the sun's rays emanate from the sun globe. Until one surpasses the glare of the brahmajyoti, one cannot receive information of the land of the Lord. The impersonalist philosophers, blinded as they are by the dazzling brahmajyoti, can realize neither the factual abode of the Lord nor His transcendental form. Limited by their poor fund of knowledge, such impersonalist thinkers cannot understand the all-blissful transcendental form of Lord Kṛṣṇa. In this prayer, therefore, Śrī Īśopaniṣad petitions the Lord to remove the effulgent rays of the brahmajyoti so that the pure devotee can see His all-blissful transcendental form.
By realizing the impersonal brahmajyoti, one experiences the auspicious aspect of the Supreme, and by realizing the Paramātmā, or all-pervading feature of the Supreme, one experiences an even more auspicious enlightenment. But by meeting the Personality of Godhead Himself face to face, the devotee experiences the most auspicious feature of the Supreme. Since He is addressed as the primeval philosopher and maintainer and well-wisher of the universe, the Supreme Truth cannot be impersonal. This is the verdict of Śrī Īśopaniṣad. The word pūṣan ("maintainer") is especially significant, for although the Lord maintains all beings, He specifically maintains His devotees. After surpassing the impersonal brahmajyoti and seeing the personal aspect of the Lord and His most auspicious eternal form, the devotee realizes the Absolute Truth in full.
In his Bhagavat-sandarbha, Śrīla Jīva Gosvāmī states: "The complete conception of the Absolute Truth is realized in the Personality of Godhead because He is almighty and possesses full transcendental potencies. The full potency of the Absolute Truth is not realized in the brahmajyoti; therefore Brahman realization is only partial realization of the Personality of Godhead. O learned sages, the first syllable of the word bhagavān (bha) has two meanings: the first is 'one who fully maintains,' and the second is 'guardian.' The second syllable (ga) means 'guide,' 'leader' or 'creator.' The syllable vān indicates that every being lives in Him and that He also lives in every being. In other words, the transcendental sound bhagavān represents infinite knowledge, potency, energy, opulence, strength and influence-all without a tinge of material inebriety."
The Lord fully maintains His unalloyed devotees, and He guides them progressively on the path toward devotional perfection. As the leader of His devotees, He ultimately awards the desired results of devotional service by giving Himself to them. The devotees of the Lord see the Lord eye to eye by His causeless mercy; thus the Lord helps His devotees reach the supermost spiritual planet, Goloka Vṛndāvana. Being the creator, He can bestow all necessary qualifications upon His devotees so that they can ultimately reach Him. The Lord is the cause of all causes. In other words, since there is nothing that caused Him, He is the original cause. Consequently He enjoys His own Self by manifesting His own internal potency. The external potency is not exactly manifested by Him, for He expands Himself as the puruṣas, and it is in these forms that He maintains the features of the material manifestation. By such expansions, He creates, maintains and annihilates the cosmic manifestation.