"This is the question of faith. And without faith, you cannot reach the kingdom of God. Your experimental knowledge, your so-called defective reasons and arguments and philosophy, that will not be applicable in the transcendental field. You have to believe. You are believing in every sphere of your life. When you purchase a ticket for transferring yourself in the aeroplane, if you go on arguing, 'Sir, I am purchasing ticket. Whether this aeroplane will reach? Whether it will not, I mean to say, crash on the way?' If you go on arguing, there is no question of, I mean to say, getting on the aeroplane. You have to believe that 'Aeroplane will take me to the other side.' You are doing that. There is no argument.
So similarly, you have to believe. We must have faith. And we see that many faithful, great ācāryas and devotees of the Lord, they achieved success by this faith. Why shall I not follow them? Therefore the Vedic literature says that you have to follow the footprints of great ācāryas. Ācārya means great devotees who come to teach the people in general about God consciousness or Kṛṣṇa consciousness. He is called ācārya. He behaves in his life how? To think of Kṛṣṇa and he teaches his students about that. He is called ācārya. Acinoti śāstrāṇi. He knows the purport of the scriptures, and he behaves in his life and he teaches his student in that way. He is called ācārya.
In the Bhagavad-gītā in the Thirteenth Chapter you have read it that ācāryopāsanam. Ācāryopāsanam. You have to approach an ācārya. That is the way of learning transcendental knowledge in all Vedic scriptures. Tad-vijñānārthaṁ sa gurum evābhigacchet: (MU 1.2.12) 'If you want to learn that transcendental science, then you have to approach the bona fide spiritual master.' Tad-vijñānārtham. Tat means transcendental; vijñāna means science. If you want to learn. So the Vedic literature teaches us to accept the authorized bona fide spiritual master ācārya. Kṛṣṇa is the head of all ācāryas. He is the principal ācārya. From Kṛṣṇa, Brahmā learned this Vedic literature. From Brahmā, Nārada learned this Vedic literature. From Nārada, Vyāsadeva; from Vyāsadeva, Madhvācārya. From Madhvācārya, so many. In this way the paramparā system, the ācārya system, is coming down. So we have to believe that. Mahājano yena gataḥ sa panthāḥ (CC Madhya 17.186). Everywhere, the footprints of ācāryas are followed. Just like in your country you are following the footprints of Lord Jesus Christ. Yes, that is the way. Or any ācārya. Because the ācārya, they come here to teach us about Kṛṣṇa consciousness, or God consciousness. That is their business. They have no other business. That is bona fide ācārya."
(Srila Prabhupada Lecture, New York, December 16, 1966)