In Vedic literature it is said that everything is Brahman and nothing else. The whole cosmic manifestation rests on the Brahman effulgence. The impersonalists, however, cannot understand how such a huge cosmic manifestation can rest on a person. Thus this inconceivable power of the Supreme Personality of Godhead is not understood by the impersonalists; therefore they are puzzled and always denying that the Absolute Truth is a person. This wrong impression is cleared by Lord Śiva himself, who says that the impersonal Brahman, which is spread all over the universe, is nothing but the Supreme Lord Himself. Here it is clearly said that the Lord is spread everywhere, just like the sunshine, by virtue of His Brahman feature. This example is very easy to understand. All the planetary systems are resting upon the sunshine, yet the sunshine and the source of sunshine are aloof from the planetary manifestations. Similarly, the sky or air is spread everywhere; air is within a pot, but it also touches filthy places and sanctified places alike. In any case, the sky is uncontaminated. The sunshine also touches filthy places and sanctified places, and both are actually produced by the sun, but in any case the sun is aloof from all filthy things. Similarly, the Lord exists everywhere. There are pious things and impious things, but in the śāstras the pious things are described as the front of the Supreme Lord, whereas impious things are described as the back of the Supreme Personality of Godhead. In Bhagavad-gītā (9.4) the Lord clearly says:

mayā tatam idaṁ sarvaṁ
 jagad avyakta-mūrtinā
mat-sthāni sarva-bhūtāni
 na cāhaṁ teṣv avasthitaḥ

“By Me, in My unmanifested form, this entire universe is pervaded. All beings are in Me, but I am not in them.”

This verse of Bhagavad-gītā explains that the Lord is spread everywhere by virtue of His Brahman feature. Everything rests in Him, yet He is not there. The conclusion is that without bhakti-yoga, without rendering devotional service to the Lord, even an impersonalist cannot understand the brahma-tattva, the Brahman feature. In the Vedānta-sūtra it is stated, athāto brahma-jijñāsā. This means that Brahman, Paramātmā or Parabrahman should be understood. In Śrīmad-Bhāgavatam also the Absolute Truth is described as the one without a second, but He is realized in three features — impersonal Brahman, localized Paramātmā and the Supreme Personality of Godhead. The Supreme Personality of Godhead is the ultimate issue, and in this verse Lord Śiva confirms that ultimately the Absolute Truth is a person. He clearly says, tat tvaṁ brahma paraṁ jyotir ākāśam iva vistṛtam. Here is a common example: a successful businessman may have many factories and offices, and everything rests on his order. If someone says that the entire business rests on such and such a person, it does not mean that the person is bearing all the factories and offices on his head. Rather, it is understood that by his brain or his energetic expansion, the business is running without interruption. Similarly, it is the brain and energy of the Supreme Personality of Godhead that carry on the complete manifestation of the material and spiritual worlds. The philosophy of monism, explained here very clearly, adjusts itself to the fact that the supreme source of all energy is the Supreme Personality of Godhead, Kṛṣṇa. This is described very clearly. It is also stated how the impersonal feature of Kṛṣṇa can be understood:

raso ’ham apsu kaunteya
 prabhāsmi śaśi-sūryayoḥ
praṇavaḥ sarva-vedeṣu
 śabdaḥ khe pauruṣaṁ nṛṣu

“O son of Kuntī [Arjuna], I am the taste of water, the light of the sun and moon, the syllable oṁ in the Vedic mantras; I am the sound in ether and ability in man.” (Bg. 7.8)

In this way Kṛṣṇa can be understood as the mystic power in everything.