apare vasudevasya devakyāṁ yācito 'bhyagāt ajas tvam asya kṣemāya vadhāya ca sura-dviṣām
Synonyms
apare—others; vasudevasya—of vasudeva; devakyām—of Devaki; yācitaḥ—being prayed for; abhyagāt—took birth; ajaḥ—unborn; tvam—you are; asya—of him; kṣemāya—for the matter of good; vadhāya—for the purpose of killing; ca—of those who are envious of the demi gods.
Translation
Some others say that being prayed by both Vasudeva and Devaki you have taken your birth as their son. Undoubtedly you are unborn and still you take your birth for their welfare as well as for killing those who are envious of the demigods.
Purport
It is also said that Vasudeva and Devaki both in their previous birth as Sutapah and Prishni underwent a severe type of penance to get the Lord as their son and as result of such austerities the Lord appeared as their son. That was only a source otherwise, as it is already declared in the Bhagwat Geeta, the Lord appeared for welfare of all people of the world and to vanquish the Asuras or the materialistic atheists.