Sage Vajashravas resolved to give away all he owned in a yajna, but he was giving old and feeble cows. His son Nachiketa was troubled to see this.
He thought that true charity is giving something one loves. He asked his father, “Father, to whom will you give me?” When he asked again and again, his father said in anger, “I give you to Yama.”
Honouring the truth, Nachiketa went to Yama’s door. Yama was away, so Nachiketa waited three days at his door, hungry and thirsty.
On returning, Yama offered three boons as atonement for the insult to a guest. For the first boon, Nachiketa asked for his father’s peace; for the second, knowledge of the fire ritual.
For the third, he asked what happens to the soul after death. Yama tried to put him off with wealth, kingdoms and pleasures, but Nachiketa held firm to his curiosity. Yama then taught him the knowledge of the Self.