Srimat Sanatana Gosvami wrote in his Brihad Bhaga-vatamrita (2.3.164-165):
nama-sankirtana prokta krisnasya prema sampadi
balistha sadhana srestha paramakarsa mantravad
tad eva manyate bhakte phala tad rasikair janai
bhagavat prema sampattau sadaivavyabhicarata
“The most intimate and powerful means to attain the treasure of love of Krisna is nama-sankirtana. It is supremely attractive, just like a mantra. That is why the rasikas (connoiseurs) also consider it to be the fruit of devotion!”
In his own commentary on this verse, Sanatana Gosvami writes:
na nu sarvesam api sadhana bhaktiprakarana premaiva phalam ityabhipreta satya nama sankirtane sati premnah avasyambhavitvat upacarena tad eva phala manyate iti
“Someone may say: ‘The fruit of all sadhana bhakti is prema, and the chanting of the holy name is just a means of its attainment. How can you then call chanting the fruit of devotion?’ The answer is: ‘Because the appearance of prema is inevitable through the practice of chanting, it has been called the fruit of devotion as well!’”
