In the Bhagavad-gita,
“I am the source of all spiritual and material worlds. Everything emanates from Me. The wise who perfectly know this engage in My devotional service and worship Me with all their hearts. (Bg.10:8)
“I am all devouring death, and I am the generator of all things yet to be. Among women I am fame, fortune, speech, memory, intelligence, faithfulness and patience. (Bg. 10.34) Because I am transcendental, beyond both the fallible and the infallible, and because I am the greatest, I am celebrated both in the world and in the Vedas as the Supreme Person.” (Bg.15.18)
Going on to the Srimad-Bhagavatam, Lord Krishna specifically explains that before, during, and after the universal creation, there is always Himself that exists.
“Brahma it is I, the Personality of Godhead, who was existing before the creation, when there was nothing but Myself. Nor was there the material nature, the cause of this creation. That which you see now is also I, the Personality of Godhead, and after annihilation what remains will also be I, the Supreme Lord.” (Bhag.2.9.33)
“Gold alone is present before its manufacture into gold products, the gold alone remains after the products’ destruction, and the gold alone is the essential reality while it is being utilized under various designations. Similarly, I alone exist before the creation of this universe, after its destruction and during its maintenance.” (Bhag.11.28.19)
“Before the creation of this cosmic manifestation, I alone existed with My specific spiritual potencies. Consciousness was then unmanifested, just as one’s consciousness is unmanifested during the time of sleep. I am the reservoir of unlimited potency, and therefore I am known as unlimited or all-pervading. From My material energy the cosmic manifestation appeared within Me, and in this universal manifestation appeared the chief being, Lord Brahma, who is your source and is not born of a material mother.” (Bhag.6.4.47-48)
“Fools deride Me when I descend in the human form. They do not know My transcendental nature and My supreme dominion over all that be.” (Bg.9.11)
“Unintelligent men, who know Me not, think that I have assumed this form and personality. Due to their small knowledge, they do not know My higher nature, which is changeless and supreme. I am never manifest to the foolish and unintelligent. For them I am covered by My eternal creative potency [yoga-maya]; and so the deluded world knows Me not, who am unborn and infallible. A Arjuna, as the Supreme Personality of Godhead, I know everything that has happened in the past, all that is happening in the present, and all things that are yet to come. I also know all living entities; but Me no one knows.” (Bg.7.24-26)
Lord Krishna also explains that he is the Supersoul of each and every living being, who exist only because of Him. He also establishes that He is the spiritual sound vibrations that can be chanted, as well as the forms of the Deities that we can see. “All living beings, moving and nonmoving, are My expansions and are separate from Me. I am the Supersoul of all living beings, who exist because I manifest them. I am the form of the transcendental vibrations like omkara and Hare Krishna Hare Rama, and I am the Supreme Absolute Truth. These two forms of Mine--namely the transcendental sound and the eternally blissful spiritual form of the Deity, are My eternal forms; they are not material.” (Bhag.6.16.51)
“My dear Uddhava, I am the cause, protector and the Lord of all mystic perfections, of the yoga system, of analytical knowledge, of pure activity and of the community of learned Vedic teachers. Just as the same material elements exist within and outside of all material bodies, similarly, I cannot be covered by anything else. I exist within everything as the Supersoul and outside of everything in My all-pervading feature.” (Bhag.11.15.35-36)
Lord Krishna goes on to explain how He is perceived by different people in different ways. “When there is agitation and interaction of the material modes of nature, the living entities then describe Me in various ways such as all-powerful time, the Self, Vedic knowledge, the universe, one’s own nature, religious ceremonies and so on.” (Bhag.11.10.34)
However, when a person reaches the vision of the Supreme by the process of Self-realization, which takes him or her above the influence of the material modes, the experience is one and the same. Then there is no more confusion about what is or what is not the highest level of spiritual realization.