By Swami Harshananda
Jānaśruti was a king and the son of Janaśruta. He was the grandson of Putra, hence was also known as Pautrāyaṇa. He was well-known for his generosity, especially for giving food to the needy, through his numerous free kitchens all over the country.
One night when he was resting on the terrace of his palace, he heard the conversation between two swans flying over his head. One swan warned the other not to cross the brilliant light above Jānaśruti’s head lest it will be harmed. The other swan spoke mockingly and compared him to the sage Raikva who was far superior.
Jānaśruti who was upset by this conversation between the birds, so he sent his men in the morning to search the sage Raikva. They finally found him sitting under a cart and scratching his skin affected by scabies. The sage Raikva taught the king Saṃvargavidyā , when the king approached him for spiritual wisdom. This incident is described in the Chāndogya Upanisad .
The same story appears in the Skandapurāna  in a slightly different, but in a more detailed form. Here, the birds are actually devarṣis . Raikva was so great that he had made all the sacred rivers stay in his hermitage as three small lakes. When Jānaśruti approached him for spiritual wisdom, he was asked to bathe in these lakes first. Then, his mind became quiet and fit enough to receive the teaching. When Raikva taught him spiritual wisdom, he attained liberation.
- Chāndogya Upanisad (4.1 to 4.3.4)
- Brahmakhanda—Setu-mādhava 29
- sages from among the gods
- The Concise Encyclopedia of Hinduism, Swami Harshananda, Ram Krishna Math, Bangalore