SB 11.17.9

śrī-bhagavān uvāca
dharmya eṣa tava praśno
 naiḥśreyasa-karo nṛṇām
varṇāśramācāravatāṁ
 tam uddhava nibodha me
Word for word: 
śrī-bhagavān uvāca — the Supreme Personality of Godhead said; dharmyaḥ — faithful to religious principles; eṣaḥ — this; tava — your; praśnaḥ — question; naiḥśreyasa-karaḥ — the cause of pure devotional service; nṛṇām — for ordinary human beings; varṇa-āśrama — the varṇāśrama system; ācāra-vatām — for those who faithfully follow; tam — those highest religious principles; uddhava — My dear Uddhava; nibodha — please learn; me — from Me.
Translation: 
The Supreme Personality of Godhead said: My dear Uddhava, your question is faithful to religious principles and thus gives rise to the highest perfection in life, pure devotional service, for both ordinary human beings and the followers of the varṇāśrama system. Now please learn from Me those supreme religious principles.
Purport: 

The word naiḥśreyasa-kara indicates that which awards the highest perfection of life, Kṛṣṇa consciousness, which the Lord is explaining to Śrī Uddhava. When considering religious principles, ordinary human beings remain bogged down in sectarian mundane considerations. The process that awards the highest perfection of life should be considered the most auspicious for human beings. The varṇāśrama system is the most scientific presentation of religiosity on the earth, and those who are most perfect in that system come to the point of Kṛṣṇa consciousness, or dedicating everything for the satisfaction of the Supreme Lord.