kṣayo vṛddhiś ca pāpmanaḥ
tadā tu bhagavān īśa
ātmānaṁ sṛjate hariḥ
yadā — whenever; yadā — whenever; hi — indeed; dharmasya — of the principles of religion; kṣayaḥ — deterioration; vṛddhiḥ — increasing; ca — and; pāpmanaḥ — of sinful activities; tadā — at that time; tu — indeed; bhagavān — the Supreme Personality of Godhead; īśaḥ — the supreme controller; ātmānam — personally; sṛjate — descends; hariḥ — the Supreme Personality of Godhead.
Whenever the principles of religion deteriorate and the principles of irreligion increase, the supreme controller, the Personality of Godhead Śrī Hari, appears by His own will.
The principles by which an incarnation of the Supreme Personality of Godhead descends upon earth are explained in this verse. The same principles are also explained in Bhagavad-gītā (4.7) by the Lord Himself:
glānir bhavati bhārata
tadātmānaṁ sṛjāmy aham
“Whenever and wherever there is a decline in religious practice, O descendant of Bharata, and a predominant rise of irreligion — at that time I descend Myself.”
In the present age, the Supreme Personality of Godhead has appeared as Śrī Caitanya Mahāprabhu to inaugurate the Hare Kṛṣṇa movement. At the present time, in Kali-yuga, people are extremely sinful and bad (manda). 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 Śrī Caitanya Mahāprabhu has inaugurated the Hare Kṛṣṇa movement, which is not different from Kṛṣṇa, the Supreme Personality of Godhead. If one associates with this movement, he directly associates with the Supreme Personality of Godhead. People should take advantage of the chanting of the Hare Kṛṣṇa mantra and thus gain relief from all the problems created in this Age of Kali.