Srimad Bhagavatam Canto 11, Chapter 26, Text 30

SB 11.26.30

bhaktim labdhavatah sadhoh
 kim anyad avasisyate
mayy ananta-gune brahmany
What more remains to be accomplished for the perfect devotee after achieving devotional service unto Me, the Supreme Absolute Truth, whose qualities are innumerable and who am the embodiment of all ecstatic experience?
Devotional service to Lord Krsna is so pleasing that a pure devotee cannot desire anything except service to the Lord. In the Tenth Canto of Srimad-Bhagavatam, Lord Krsna told the gopis that they would have to accept their own service as the ultimate reward of their devotion to Him, since nothing awards as much happiness and knowledge as devotional service itself. When one sincerely chants and hears the holy name and fame of Lord Krsna, the heart is purified and gradually one can appreciate the actual, blissful nature of Krsna consciousness, loving service to the Lord.
Srimad Bhagavatam Canto 11, Chapter 26, Text 29
Srimad Bhagavatam Canto 11, Chapter 26, Text 31