Whenever the principles of religion deteriorate and the principles of irreligion increase, the supreme controller, the Personality of Godhead Sri Hari, appears by His own will.

In the present age, the Supreme Personality of Godhead has appeared as Sri Caitanya Mahaprabhu to inaugurate the Hare Krsna movement. At the present time, in Kali-yuga, people are extremely sinful and bad…. They have no idea of spiritual life and are misusing the benefits of the human form to live like cats and dogs. Under these circumstances Sri Caitanya Mahaprabhu has inaugurated the Hare Krsna movement, which is not different from Krsna, the Supreme Personality of Godhead. If one associates with this movement, he directly associates with the Supreme Personality of Godhead. People should take advantage … and thus gain relief from all the problems created in this Age of Kali.

Srimad-Bhagavatam 9.24.56, translation and purport extracts by Srila Prabhupada