Ṛbhu

Ṛbhu was a son of Brahmā, the creator, and knew the truth of things by his very nature. His pupil Nidāgha received all his knowledge, but had not taken in its heart, the sense that all is one. So after a thousand years of the gods, for whom a whole year of men is a single day and night, Ṛbhu came to Nidāgha's door as a stranger and asked for a meal, and after another thousand he came again and found him standing apart from the crowd while a king rode into the city on an elephant. Both times Nidāgha came to know his teacher, and the second time he learned to see all beings as one with himself.