So the principle . . . what is that principle? Sarva-dharmān parityajya mām ekaṁ śaraṇaṁ vraja (BG 18.66). This is principle. "You give up all these nonsense activities. Simply surrender." So one who has surrendered to Kṛṣṇa fully, no other business, he is guru. This is the definition of guru. There is no difficult to understand who is guru. One who follows strictly the principles laid down by jagad-guru, he is guru. So the jagad-guru says . . . because we have to learn everything, especially spiritual subject matter, from guru. Tad-vijñānārthaṁ sa gurum eva abhigacchet (MU 1.2.12). This is the injunction of the Vedas. If you want to understand Brahman, athāto brahma jijñāsā . . . this life, human life, is meant for inquiring about the Absolute Truth: athāto brahma jijñāsā. This is not meant for any other purpose. This life, any life, there is no question of inquiring about "Where shall I eat? Where shall I sleep? Where shall I have sex? How shall I be saved from fear?" There is no such question. This is already arranged. These things are already arranged even for the birds and beast. They are also living. They are also eating. They are also sleeping. They are also having sex life. They also defend them from danger. So by nature the arrangement is already there. So only thing is, difference than in other life . . . there are 8,400,000 . . . so eighty-million, 8,000,000 lives, they do not know except these things. And out of the four millions, eight million, four . . . 400,000 human species, so mostly they are like animals. So unless one comes to the Vedic civilization, he's not human being. He's not human being.
So when one comes to the Vedic principle, then the question is athāto brahma jijñāsā. Vedānta-sūtra says: "Now you have come to the real platform. You inquire about Brahman." Jijñāsuḥ śreya uttamam. Tasmād guruṁ prapadyeta jijñāsuḥ (SB 11.3.21). When one is inquisitive to inquire about the higher-level questions, brahma-jijñāsā, then he requires a guru. Tasmād guruṁ prapadyeta: "You are now inquisitive about understanding higher-level knowledge, so you must go to a guru." Tasmād guruṁ prapadyeta. Who? Jijñāsuḥ śreya uttamam. Uttamam. Uttamam means that which is above this darkness. This whole world is darkness. So one who wants to go above darkness . . . tamasi mā jyotir gama. The Vedic injunction is: "Don't keep yourself in darkness. Go to the light." That light is Brahman, brahma-jijñāsā.