A short story from Chandogya Upanisad
Long ago, there were two men of wisdom (Rsi-s) who lived in a peaceful and quiet hermitage in the middle of the forest. They were ardent devotees of the wind God Vayu, and spent most of their time offering chants and rituals to honor him.
One afternoon, just as they were about to begin their meal, a beggar arrived holding his begging bowl and made a sincere request to them. "Pardon me respectful sages, could I beg for a part of your excess meal so I can sustain myself?"
"Sorry young man, we cannot spare you any food," retorted one of the sages.
Unperturbed, the young monk continued, "Sir, you look very pious. May I ask you most humbly, which God do you worship?"
With great pride the sage answered "we worship Vayu, the wind god. He is also known as Prana, the breath of life."
"Thats wonderful! Then you must know that Prana pervades the whole universe" said the beggar.
The sages were getting impatient, "Yes, yes, we know all that young man."
The beggar further prodded them, "Oh respectful sages, could you kindly tell me to whom did you make this food-offering?"
"Prana, the life, who else?" said the sage, who was now visibly irritated.
The young monk smiled and responded, "Sir, if life pervades the universe, it pervades me too. Am I not a part of that universe?"
"Yes, that's right" replied the sage, who was as puzzled as he was agitated.
"It is Prana, or life, that pulsates in me, as this hungry body of mine stands before you and speaks," appealed the beggar.
The sages were now trapped in the argument and admitted, "This is correct. You speak the truth."
The bold beggar then made his final appeal, "Then Oh revered sages, in denying me food, you are denying Prana for whom you have prepared the food."
The sages were stunned and had no answer to this. They instantly realized that mere reading of scriptures can not assure them of true understanding. Ashamed at their ignorant act, they gladly shared their food with the young beggar.