Vishnupurana 2.15.p2

2.15.p2

The Brahmin said—"Hear O great king what in the days of yore Ribhu said for the instruction of illustrious Nidagka. The great patriarch Brahmā had a son by Ribhu, who was by nature, O king, conversant with true wisdom. A son of Pulastya by name Nidagha became his disciple and (Ribhu) greatly delighted gave him various instructions. O lord of men, he being thus instructed, Ribhu did not doubt of his being fully confirmed in the doctrines of unity.