So, na me viduḥ sura-gaṇāḥ prabhavaṁ na maharṣayaḥ aham adir 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 adir 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). 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. It is one of the Upaniṣads. You have read Upaniṣad. The Bhagavad-gītā is also one of the Upaniṣads, and therefore Bhagavad-gītā is known as Gītopaniṣad.
So if nobody knows the Supreme Personality of Godhead, then how He can be known? If He is not known to the demigods, if He is (not) known to the great sages, then how He can be known? Yes. He can be known. He can be known in this way. When the Supreme Lord comes before you and He reveals Himself before you, then you can know.
You cannot know by your imperfect senses. Our senses are imperfect. We have . . . several times we have described in this meeting that our senses cannot realize the Supreme Truth. Ataḥ śrī-kṛṣṇa-nāmadi na bhaved grāhyam indriyaiḥ (CC Madhya 17.136). Our senses are so imperfect that simply by expanding the sense power artificially, speculating, we cannot realize. These are described in different way in different scriptures.
So He can be known how? That is also described—sevonmukhe hi jihvādau svayam eva sphuraty adaḥ: when you become in a submissive attitude and you chant. Jihvādau. Jihvādau means the realization begins from the tongue. God realization begins from the tongue. Therefore the tongue's function is to eat and to vibrate sound. So these two processes, vibration of Hare Kṛṣṇa, Hare Kṛṣṇa, Kṛṣṇa Kṛṣṇa, Hare Hare / Hare Rāma, Hare Rāma, Rāma Rāma, Hare Hare, and eating kṛṣṇa-prasāda. You cannot allow your tongue to taste anything and everything.
If you can control your tongue for eating kṛṣṇa-prasāda, and if you engage your tongue in vibrating the transcendental sound Hare Kṛṣṇa, then sevonmukhe hi jihvādau (Bhakti-rasāmṛta-sindhu 1.2.234). By this submissive process that, "I surrender my tongue to the Supreme Personality of Godhead," then by controlling the tongue, you controlling all other senses. You go to a straight line from the tongue to the down, all senses will be controlled. And if you cannot control your tongue, then you cannot control your senses.
So the first and foremost thing is that you control your tongue. Don't allow your tongue to taste and everything and anything. Kṛṣṇa has given us so many nice preparation. Day before yesterday we were present here, we had feasting. Everybody has tasted. So many nice things we have got. Kṛṣṇa baṛo doyāmoy, koribāre jihwā jay, swa-prasād-anna dilo bhāi (Prasāda-sevāya I). Our tongue is very fastidious. He wants to taste this, taste this, taste this. But Kṛṣṇa is so kind that He gives us varieties of prasādam so you can taste them, you can satisfy your desire, at the same time you become spiritually advanced. This is a nice process.