It is said in the Śrīmad-Bhāgavatam, ataḥ śrī-kṛṣṇa-nāmādi na bhaved grāhyam indriyaiḥ (CC Madhya 17.136). Our senses are imperfect always. Even we cannot understand perfectly the material world. Just like we are seeing so many planets and stars in the sky at night, but we do not know what they are. We do not know even what is this moon planet. We are trying for so many years, trying to go there in Sputnik and . . . even one planet. Even we do not know what varieties are there even in this planet. If you go on the sea, if you go on the sky, you are perfectly illusioned.
So our knowledge is always imperfect. That we must admit. If foolishly, if we think we have acquired all sorts of knowledge, we have advanced in science, this is another foolishness. It is not possible. So when it is not possible to understand even the material things which we are daily seeing with our eyes and perception, what to speak of spiritual? And the Kṛṣṇa, or the Supreme Personality of Godhead, He is the Supreme spiritual form. So it is not possible for us to understand Kṛṣṇa by our limited senses.
18:44 Then why we are bothering so much for Kṛṣṇa consciousness if it is not possible? The answer is ataḥ śrī-kṛṣṇa-nāmadi na bhaved grāhyam indriyaiḥ. These imperfect senses cannot realize Kṛṣṇa as He is. Then the process is sevonmukhe hi jihvādau. If you become submissive, if you develop the spirit of service to Kṛṣṇa—either as servant or as friend or as parent or as lover, if you begin to give service to the Supreme Lord . . . the beginning of service is chanting. Therefore it is said, jihvādau. Jihvādau means . . . jihva means tongue. Tongue. Your service begins by the tongue. How? By the tongue you can chant Hare Kṛṣṇa, and by the tongue you can taste Kṛṣṇa's prasāda.
So the beginning process is very nice. You chant Kṛṣṇa, Hare Kṛṣṇa, Hare Kṛṣṇa, and whatever little prasāda is offered to you by Kṛṣṇa by His kindness, you accept it. Then the result will be that sevonmukhe hi jihvādau. If you become submissive and if you begin this service, chanting and eating prasāda, then svayam eva sphuraty adaḥ, simply by these two kinds of practices, Kṛṣṇa will Himself reveal Himself before you: "I am like this." You cannot understand Kṛṣṇa by speculation. No. That is not possible, because your senses are imperfect. But if you begin this process of service, then it will be possible that one day Kṛṣṇa will reveal to you, "I am like this."
Just like Kṛṣṇa is revealing in the Bhagavad-gītā to Arjuna. Arjuna is a devotee, and he is submissive. And he is friend also. He is in contact with Kṛṣṇa as friend. Therefore Kṛṣṇa is revealing to Kṛṣṇa . . . ah, to Arjuna. This Bhagavad-gītā is spoken to Arjuna, not to any Vedāntist or speculationist.
In the beginning of the Fourth Chapter, you know that Kṛṣṇa says that "I'll speak to you that old system of yoga, bhakti-yoga," in the beginning of the Fourth Chapter, "unto you." Why? Kṛṣṇa was not a Vedāntist . . . ah, Arjuna was not a Vedāntist or a great philosopher or a Brāhmin or nothing. He was a Kṣatriya. He was a fighter and a householder, not even a sannyāsī. So these are not qualifications to understand Kṛṣṇa.
Suppose . . . just like I have become a sannyāsī, mendicant. This is not qualification that I can understand Kṛṣṇa. Even in your white dress, as gṛhastha, you can understand better than me. Then what is the qualification? This qualification: sevonmukhe hi jihvādau (Brs. 1.2.234). One who has developed the service spirit with love and devotion, he can understand Kṛṣṇa. Nobody else. Nobody . . . not Dr. Radhakrishnan or similar person. No. But a child can understand Kṛṣṇa if he has full faith in Him.