Sum and substance

The duty of saintly persons, therefore, is to take up seriously the cause of sanatana-dharma and try to reestablish it for the benefit of the entire human society. The Krishna consciousness movement has been started according to this principle. As stated in Srimad-Bhagavatam (12.3.51):

kaler dosha-nidhe rajan

asti hy eko mahan gunah

kirtanad eva krishnasya

mukta-sangah param vrajet

The entire Kali-yuga is full of faults. It is like an unlimited ocean of faults. But the Krishna consciousness movement is very authorized. Therefore, following in the footsteps of Sri Caitanya Mahaprabhu, who five hundred years ago inaugurated the movement of sankirtana, krishna-kirtana, we are trying to introduce this movement, according to superior orders, all over the world. Now, if the inaugurators of this movement strictly follow the regulative principles and spread this movement for the benefit of all human society, they will certainly usher in a new way of life by reestablishing sanatana-dharma, the eternal occupational duties of humanity. The eternal occupational duty of the human being is to serve Krishna. Jivera 'svarupa' haya -- krishnera 'nitya-dasa.' [Cc. Madhya 20.108]. This is the purport of sanatana-dharma. Sanatana means nitya, or "eternal," and krishna-dasa means "servant of Krishna." The eternal occupational duty of the human being is to serve Krishna. This is the sum and substance of the Krishna consciousness movement.

SB 8.14.4