Here is a story from Katha Upanishad. In this story a young man got this highest knowledge from Yama, the God of Death, by his courage of conviction. Long, long ago, there lived poor Brahmin called Vajasravas. He performed a sacrifice called Visvajit. In that sacrifice one has to give away everything that belongs to him.
Nothing is to be kept back.
Accordingly, this brahmin gave away all that belonged to him. They were necessarily things of poor value like aged cows and old vessels. This man had a son named Nachiketas. He was an intelligent boy. He felt unhappy that his father's gifts were of little value.