SB Canto 3
O Lord, persons who, because of their serious attitude, attain the stage of enlightened devotional service achieve the complete meaning of renunciation and knowledge.
SB 3.5.46, Translation and Purport: O Lord, persons who, because of their serious attitude, attain the stage of enlightened devotional service achieve the complete meaning of renunciation and knowledge and attain the Vaikuṇṭhaloka in the spiritual sky simply by drinking the nectar of Your topics. The difference between the impersonalistic mental speculators and the pure devotees of the Lord is that the former pass through a miserable understanding of the Absolute Truth at every stage, whereas the devotees enter into the kingdom of all pleasures even from the beginning of their attempt. The devotee has only to hear about devotional activities, which are as simple as anything in ordinary life, and he also acts very simply, whereas the mental speculator has to pass through a jugglery of words, which are partially facts and partially a make-show for the maintenance of an artificial impersonal status. In spite of his strenuous efforts to attain perfect knowledge, the impersonalist attains merging into the impersonal oneness of the brahmajyoti of the Lord, which is also attained by the enemies of the Lord simply because of their being killed by Him. The devotees, however, attain to the highest stage of knowledge and renunciation and achieve the Vaikuṇṭhalokas, the planets in the spiritual sky. The impersonalist attains only the sky, and does not achieve any tangible transcendental bliss, whereas the devotee attains to the planets where real spiritual life prevails. With a serious attitude, the devotee throws away all achievements like so much dust, and he accepts only devotional service, the transcendental culmination.
Bhagavad-gita As It Is Lectures
That seriousness, one who has taken that serious attitude, they can actually perform this Kṛṣṇa consciousness very nicely.
Lecture on BG 9.20-22 -- New York, December 6, 1966: "This material existence, either this Svargaloka or the heavenly planet or this planet or that, will never give me happiness. I will have to... As Kṛṣṇa informs herein, that yad gatvā na nivartante tad dhāma paramaṁ mama [Bg. 15.6], I will have to enter the kingdom of God, spiritual planet, where going I will have not to return back again to accept this material body." That seriousness, one who has taken that serious attitude, they can actually perform this Kṛṣṇa consciousness very nicely. But those who are still under the impression that "Material advancement will make me happy," they are still under the spell of illusion. Daivī hy eṣā guṇamayī mama māyā duratyayā [Bg. 7.14].
It is factual, because the leaders of the society should have taken Krishna Consciousness in such serious attitude as described by you.
Letter to Madhudvisa -- New Vrndavana 7 September, 1972: I beg to acknowledge receipt of your letters and Vyasa Puja offerings dated August 26, 1972. Your presentation of Vyasa Puja offering stands first. You are eligible for the first prize. Although it is imagination, still it is so nicely descriptive and systematic, that it proves how much you have perfect knowledge in other fields of activities, namely political, social, and economical. Thank you very much. Your ideas are not exactly imagination. It is factual, because the leaders of the society should have taken Krishna Consciousness in such serious attitude as described by you. The president of the United States, the Queen of England, the Communist leaders, all business magnates, all should have taken this movement seriously for the upliftment of human society, but because most of them are miscreants, rascals, lowest of the mankind, and lost of all real knowledge, they are still unaware of the importance of the Krishna Consciousness Movement.