Srimad Bhagavatam Canto 11, Chapter 11, Text 47

SB 11.11.47

ista-purtena mam evam
 yo yajeta samahitah
labhate mayi sad-bhaktim
 mat-smrtih sadhu-sevaya
 
Translation: 
 
One who has executed sacrificial performances and pious works for My satisfaction, and who thus worships Me with fixed attention, obtains unflinching devotional service unto Me. By the excellent quality of his service such a worshiper obtains realized knowledge of Me.
 
Purport: 
 
The word ista-purtena, which means “sacrificial performances and pious works,” does not indicate deviation from the pure devotional service of the Lord. Lord Krsna, or Visnu, is called Yajña, or the Lord of sacrifice, and in Bhagavad-gita (5.29) Lord Krsna says, bhoktaram yajña-tapasam: “I am the actual enjoyer of all sacrifice.” The highest sacrifice is to chant the holy names of the Lord, and by taking shelter of the Lord’s names, one will acquire unflinching devotion and realized knowledge of the Absolute Truth. A realized devotee is very attentive in his devotional service, taking it as his life and soul. He keeps himself fit for devotional service by constantly worshiping and glorifying the lotus feet of the spiritual master and the Supreme Personality of Godhead. Such hari-nama-kirtana and guru-puja are the only practical methods by which one can achieve pure devotional service. When hari-kirtana is expanded, it is called krsna-sankirtana. One should not dry up by performing unauthorized austerities or sacrifices; rather, one should engage with all enthusiasm in the great sacrifice of sri-krsna-sankirtana, which enables one to easily achieve the highest perfection of human life.
Srimad Bhagavatam Canto 11, Chapter 11, Text 46
Srimad Bhagavatam Canto 11, Chapter 11, Text 48