Srimad Bhagavatam Canto-04, Chapter-04, Text-33
deva utpetur ojasa
rbhavo nama tapasa
somam praptah sahasrasah
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
When Bhrgu Muni offered oblations in the fire, immediately many thousands of demigods named Rbhus became manifested. All of them were powerful, having achieved strength from Soma, the moon.
Purport by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
It is stated here that many thousands of demigods named Rbhus became manifested because of the oblations offered in the fire and the chanting of the hymns from the Yajur Veda. Brahmanas like Bhrgu Muni were so powerful that they could create such powerful demigods simply by chanting the Vedic mantras. Vedic mantras are still available, but the chanters are not. By chanting Vedic mantras or chanting the Gayatri or rg-mantra one can attain the results one desires. In the present Age of Kali it is recommended by Lord Caitanya that simply by chanting Hare Krsna one can attain all perfection.
[To hear more on this verse, visit – http://www.srimadbhagavatamclass.com/srimad-bhagavatam-canto-04-chapter-04-text-33/]