Story of King Janashruti and cart puller Raikva is found in
fourth chapter of Chandogya Upanishad. King Janashruti had attained luminous
spiritual power by offering food to people. He built dharamshalas and eateries
in all villages and towns in his country to ensure that no one slept without
food.
One day the king was resting on the terrace of his palace. Two
swans happened to be flying over the palace. One swan warned the other swan not
to go near the king and disturb him, as his spiritual power will destroy it.
The other swan retorted by saying that the king is not as
great as you think as there is a cart puller named Raikva in whom all virtue
and wisdom resided. He is the greatest.
King Jan Shruti overheard the conversation and was curious
to meet cart puller Raikva. After long search, the king was able to locate
Raikva. The king made several offers to entice Raikva to make him his disciple.
But the king was unsuccessful. The king then threatened the cart puller but it
also had no effect on him.
Finally, the king shed his kingly powers and appeared before
Raikva as a simple man. Now Raikva relented and taught him many truths.
The teachings are found in the Chandogya Upanishad.