Kṛṣṇa says, ya idaṁ paramaṁ guhyaṁ mad-bhakteṣv abhidhāsyati (BG 18.68). This paramaṁ guhyam. What is that paramaṁ guhyam? Sarva-dharmān parityajya mām ekaṁ śaraṇaṁ vraja (BG 18.66). This is paramaṁ guhyam, Kṛṣṇa said. Guhyād guhyatamam. What is that verse? Who can say? Just before saying sarva-dharmān parityajya, Kṛṣṇa said that "You are My very dear friend. Therefore I am talking to you the most confidential part of knowledge." Is it not? What is that confidential part? Sarva-dharmān parityajya: "Give up everything. Simply surrender unto Me." This is confidential knowledge. Jñāna, karma, yoga, this will not help. It will take some time. You can waste your time in that way, you are at liberty, but real dharma is that "You fully surrender unto Me. Don't talk nonsense." Arjuna was talking so many nonsense things. So Kṛṣṇa ultimately said, "My dear Arjuna, you are My confidential friend. Therefore I am asking you. You do this. Don't waste your time. It will not help." It will help—bahūnāṁ janmanām ante (BG 7.19). You can go on with your learning, with your study of Vedas, with your practice of yoga or ritualistic ceremonies, karma-kāṇḍa, jñāna-kāṇḍa, but unless you come to this point—sarva-dharmān parityajya mām ekaṁ śaraṇaṁ vraja (BG 18.66)—there is no happiness. That is not possible. This is the confidential . . .
So if this confidential knowledge, one who preaches without any compromise, he is the confidential servant of Kṛṣṇa. There is no compromise. This is real religion. The Kṛṣṇa says, na ca tasmān manuṣyeṣu kaścid me priya-kṛttamaḥ (BG 18.69). So this is the person who has received the authority to draw mercy water from the ocean of mercy of Kṛṣṇa. Sākṣād-dharitvena samasta-śāstraiḥ. And what Kṛṣṇa said five thousand years ago, the same thing Caitanya Mahāprabhu said. Same thing. There was no change, as there was no change between the statement of Viśvanātha Cakravartī Ṭhākura and Narottama dāsa Ṭhākura. Sādhu śāstra. As śāstra, there is no change. Not that "Modernize. The śāstra should be changed." No. That is nonsense. That is not śāstra. Śāstra cannot be changed. "Circumstantially, it will be changed, seasonal changes." No. That is not śāstra. Śāstra means it is perpetual. What Kṛṣṇa said five thousand years ago or Kṛṣṇa said some forty millions of years ago to the sun god . . . Imaṁ vivasvate yogaṁ proktavān aham avyayam (BG 4.1). He says, "I am talking to you that purātanaṁ yogam." Not that "Because it has passed millions of years and now it is a different time, so I will have to change." No. He said, "I am talking to you that very old system." Is it not? Just see. The śāstra cannot be changed. God's word cannot be changed. Then what is the difference between God and ourself? He is always perfect. He is always perfect. What He said forty millions of years ago, what He said five thousand years ago, that is also correct up to date. That is śāstra. Not that "So many years have passed and it has become old. Now let us reform it and put it into new way." No. You can put the same thing in a new way, but you cannot change the principle. Sādhu śāstra guru-vākya, tinete kariyā aikya. Śāstra is never changed. And the sādhu . . . Sādhu means who follows the śāstras. He is sādhu. He also does not change. Sādhu, śāstra. And guru? Guru means who follows the śāstra and sādhu. So there are three, the same. A guru will not change, that "It was spoken five thousand years ago. That is not applicable now. Now I am giving you something new, jugglery." He is useless. Sādhu śāstra guru-vākya tinete kariyā aikya. Yaḥ śāstra-vidhim utsṛjya vartate kāma kārataḥ, na siddhim avāpnoti (BG 16.23). These things are there.