Butcher who enlightened the saint

A young saint went to a forest and meditated for a long time. After years of hard work and practice, he was sitting under a tree one day. When some dry leaves fell upon his head, he looked up and saw a crow and a crane fighting on the top of the tree, which made him very angry. He angrily glanced at them, a flash of fire went out of his head — such was the power of the saint and burnt the birds to ashes! He was very glad at this development of power — he could burn the the crow and the crane just by a look

After sometime he had to go to the town to beg his bread (In India it was a common practice for the saint to seek alms for their living). He went, stood at a door, and begged for food. A woman's voice came from inside the house, "Wait a little, my son." The young man thought, "You wretched woman, how dare you make me wait! You do not know my power yet." While he was thinking thus the voice came again: "Boy, don't think too much. Here is neither crow nor crane." He was astonished; still he had to wait. At last the woman came, and he fell at her feet and said

Saint : "Mother, how did you know that?"

Woman : "I am a common woman. I made you wait because my husband is ill and I was nursing him. When I was unmarried, I did my duty to my parents; now that I am married, I do my duty to my husband; that is all I practice. But by doing my duty I have become illumined and thus I could read your thoughts and know what you had done in the forest. If you want to know something higher than this, go to the market of this town where you will find a butcher"

The saint thought, "Why should I go to a butcher?". But after what he had seen, his mind opened a little, so he went. When he came near the town, he found the market and there saw, at a distance, a big fat butcher cutting meat with big knives, talking and bargaining with different people. The saint thought, "O Lord help me! Is this the man from whom I am going to learn? He is the incarnation of a demon, if he is anything". 

In the meantime the butcher looked up and said, "O Saint, did that lady send you here? Take a seat until I have done my business". The saint took his seat; the butcher went on with his work and after he had finished, he took his money and said to the saint, "Come sir, come to my home" On reaching home, the butcher gave him a seat asking the saint to wait and went into the house.

The butcher then washed his old father and mother, fed them, and did all he could to please them, after which he came to the saint and asked, "Now, sir, you have come here to see me; what can I do for you?" The saint asked him a few questions about God and the butcher gave him a lecture which forms a part of the Mahabharata, called Vyâdha-Gitâ, which contains one of the highest spiritual wisdom ever recorded. When the butcher finished his teaching, the saint was taken aback.

Saint asked "Why are you in that body? With such knowledge as yours why are you in a butcher's body, and doing such filthy, ugly work?"

Butcher said "My son, no duty is ugly, no duty is impure. My birth placed me in these circumstances and environments. I am unattached and I try to do my duty well. I try to do my duty as a householder and I try to do all I can to make my father and mother happy. I neither know yoga, nor have I become a saint nor did I go out of the world into a forest; nevertheless, all that you have heard and seen has come to me through the unattached doing of the duty which belongs to my position"

[Extracted from Complete Works of Swami Vivekananda - Volume 1 / Karma Yoga / Chapter 4 : What is duty?]