Krishna is known not through speculation but through surrender, service, and the purification of one's senses.Listen — Srila Prabhupada Uvaca
Bhagavad-gītā 10.2–3 — January 2, 1967, New York 670102BG-NEW YORK [28:01 Minutes] Prabhupāda: na me viduḥ sura-gaṇāḥ prabhavaṁ na maharṣayaḥ aham ādir hi devānāṁ maharṣīṇāṁ ca sarvaśaḥ [Bg. 10.2] [Neither the hosts of demigods nor the great sages know My origin, for, in every respect, I am the source of the demigods and the sages.] So Lord Kṛṣṇa says that nobody knows Him. Aham ādir hi devānām. If you... What to speak of the human society, even you take the demigods, who are more intelligent and more advanced than the human society in other planets, they also do not know.
And maharṣayaḥ. Maharṣayaḥ means that seven great sages. Their planet is near the polestar. You have seen it that like asking questions, seven stars.
So these stars are different planets for different great sages. They also do not know. So, na me viduḥ sura-gaṇāḥ prabhavaṁ na maharṣayaḥ aham ādir hi devānām [Bg. 10.2]: "I am the original... I am the source of all these maharṣayaḥ, all these demigods." He's the father of everyone. Maharṣīṇāṁ ca sarvaśaḥ: "I am not only the origin of these demigods, but I am also the origin of all these great sages." That means He is the origin of this universe.
In the Śrīmad-Bhāgavatam it is very nicely described how this universal form took place and how Brahmā was created and from Brahmā the ṛṣis were created, how population increased generally. These descriptions are there. So actually, He is the origin. Janmādy asya yataḥ [SB 1.1.1].
As it is said in the Vedānta-sūtra, everything is emanating from Him. So He's also... According to this version, He's also origin of Paramātmā, the Supersoul. And He is also the origin of nirviśeṣa, or impersonal brahma-jyotir. Because it is said, aham ādir hi devānāṁ maharṣīṇāṁ ca sarvaśaḥ.
Sarvaśaḥ means, "Anything that you have any conception of, of all them, I am the supreme source." Therefore, as it is stated in the Śrīmad-Bhāgavatam, the Absolute Truth is realized in three phases, that vadanti tat tattva-vidas tattvaṁ yaj jñānam advayam [SB 1.2.11]. [Learned transcendentalists who know the Absolute Truth call this nondual substance Brahman, Paramātmā or Bhagavān.] Advayam means nonduality, one. The one Supreme Truth, Absolute Truth, is realized in three phases, brahmeti paramātmeti bhagavān iti śabdyate: realization of the impersonal Brahman, or the glowing effulgence, just like sunshine; then the localized Supersoul; then Bhagavān, the Supreme Personality of Godhead. And there are many expansion of the Supreme Personality of Godhead: Nārāyaṇa, Adhokṣaja... There are many, innumerable planets in the spiritual world, and all of them are emanation from the Kṛṣṇa planet. And the Kṛṣṇa planet, the supreme Deity is Kṛṣṇa. This description we have got in several Vedic literatures—Brahma-saṁhitā and Vedānta-sūtra, Bhāgavata, in Purāṇas, in Upaniṣad.
Everywhere these descriptions are there. Those who are scholarly student, they'll get information, and the whole thing is summarized in Bhagavad-gītā. Therefore Bhagavad-gītā is known also as Gītopaniṣad. At the end of every chapter you'll find these things are written, gītāsu or upaniṣatsu.