vinäçäya ca duñkåtäm
sambhavämi yuge yuge
pariträëäya—for the deliverance; sädhünäm—of the devotees; vinäçäya—for the annihilation; ca—also; duñkåtäm—of the miscreants; dharma—principles of religion; saàsthäpana-arthäya—to reestablish; sambhavämi—I do appear; yuge—millennium; yuge—after millennium.
In order to deliver the pious and to annihilate the miscreants, as well as to reestablish the principles of religion, I advent Myself millennium after millennium.
According to Bhagavad-gétä, a sädhu (holyman) is a man in Kåñëa consciousness. A person may appear to be irreligious, but if he has the qualifications of Kåñëa consciousness wholly and fully, he is to be understood to be a sädhu. And duñkåtam applies to one who doesn't care for Kåñëa consciousness. Such miscreants, or duñkåtam, are described as foolish and the lowest of mankind, even though they may be decorated with mundane education; whereas another person, who is one hundred percent engaged in Kåñëa consciousness, is accepted as sädhu, even though such a person may neither be learned nor well cultured. As far as the atheistic are concerned, it is not necessary for the Supreme Lord to appear as He is to destroy them, as He did with the demons Rävaëa and Kaàsa. The Lord has many agents who are quite competent to vanquish demons. But the Lord especially descends to appease His unalloyed devotees, who are always harassed by the demonic. The demon harasses the devotee, even though the latter may happen to be his kin. Although Prahläda Mahäräja was the son of Hiraëyakaçipu, he was nonetheless persecuted by his father; although Devaké, the mother of Kåñëa, was the sister of Kaàsa, she and her husband Vasudeva were persecuted only because Kåñëa was to be born of them. So Lord Kåñëa appeared primarily to deliver Devaké, rather than kill Kaàsa, but both were performed simultaneously. Therefore it is said here that to deliver the devotee and vanquish the demon miscreants, the Lord appears in different incarnations.
In the Caitanya-caritämåta of Kåñëadäsa Kaviräja, the following verses summarize these principles of incarnation:
såñöi-hetu yei mürti prapaïce avatare
sei éçvara-mürti ‘avatära’ näma dhare
mäyätita paravyome savära avasthäna
viçve ‘avatäri’ dhare ‘avatära’ näma.
"The avatära, or incarnation of Godhead, descends from the kingdom of God for material manifestation. And the particular form of the Personality of Godhead who so descends is called an incarnation, or avatära. Such incarnations are situated in the spiritual world, the kingdom of God. When they descend to the material creation, they assume the name avatära."
There are various kinds of avatäras, such as puruñävatäras, guëävatäras, lélävatäras, çaktyäveça avatäras, manvantara-avatäras and yugävatäras—all appearing on schedule all over the universe. But Lord Kåñëa is the primeval Lord, the fountainhead of all avatäras. Lord Çré Kåñëa descends for the specific purposes of mitigating the anxieties of the pure devotees, who are very anxious to see Him in His original Våndävana pastimes. Therefore, the prime purpose of the Kåñëa avatära is to satisfy His unalloyed devotees.
The Lord says that He incarnates Himself in every millennium. This indicates that He incarnates also in the age of Kali. As stated in the Çrémad-Bhägavatam, the incarnation in the age of Kali is Lord Caitanya Mahaprabhu, who spread the worship of Kåñëa by the saìkértana movement (congregational chanting of the holy names), and spread Kåñëa consciousness throughout India. He predicted that this culture of saìkértana would be broadcast all over the world, from town to town and village to village. Lord Caitanya as the incarnation of Kåñëa, the Personality of Godhead, is described secretly but not directly in the confidential parts of the revealed scriptures, such as the Upaniñads, Mahäbhärata, Bhägavatam, etc. The devotees of Lord Kåñëa are much attracted by the saìkértana movement of Lord Caitanya. This avatära of the Lord does not kill the miscreants, but delivers them by the causeless mercy of the Lord.