Srimad Bhagavatam Canto 07, Chapter 09, Text 50

SB 7.9.50

tat te ’rhattama namah stuti-karma-pujah
 karma smrtis caranayoh sravanam kathayam
samsevaya tvayi vineti sad-angaya kim
 bhaktim janah paramahamsa-gatau labheta
 
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada: 
 
Therefore, O Supreme Personality of Godhead, the best of all persons to whom prayers are offered, I offer my respectful obeisances unto You because without rendering six kinds of devotional service unto You — offering prayers, dedicating all the results of activities, worshiping You, working on Your behalf, always remembering Your lotus feet and hearing about Your glories — who can achieve that which is meant for the paramahamsas?
 
Purport by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada: 
 
The Vedas enjoin: nayam atma pravacanena labhyo na medhaya na bahuna srutena. One cannot understand the Supreme Personality of Godhead simply by studying the Vedas and offering prayers. Only by the grace of the Supreme Lord can one understand Him. The process of understanding the Lord, therefore, is bhakti. Without bhakti, simply following the Vedic injunctions to understand the Absolute Truth will not be helpful at all. The process of bhakti is understood by the paramahamsa, one who has accepted the essence of everything. The results of bhakti are reserved for such a paramahamsa, and this stage cannot be obtained by any Vedic process other than devotional service. Other processes, such as jñana and yoga, can be successful only when mixed with bhakti. When we speak of jñana-yoga, karma-yoga and dhyana-yoga the word yoga indicates bhakti. Bhakti-yoga, or buddhi-yoga, executed with intelligence and full knowledge, is the only successful method for going back home, back to Godhead. If one wants to be liberated from the pangs of material existence, he should take to devotional service for quick attainment of this goal.
Srimad Bhagavatam Canto 07, Chapter 09, Text 49
Srimad Bhagavatam Canto 07, Chapter 09, Text 51