One day Shankara with his disciples went for their bath in the Ganges. When they came close to the Manikarnika Ghat they saw an untouchable worker at the cremation ground at the bottom of the social scale and devoid of any culture, primitive in their sight, extremely ugly and of a terrifying shape. The man who held four dogs in leash, was approaching in a disorderly way from the opposite direction. Finding no way of avoiding the man, Shankara, greeted him and said, "Untouchable! Step aside aside with your dogs so that we can pass."
The man did not seem to listen to his words at all, and did not wait or deflect. Instead he went on. Shankara cried out again in a somewhat excited voice, "Stop, fellow, stop! A leave a passage for us."
Still the man did not care to pay heed to Shankara. The terrible-looking man burst out into hideous guffaw. Then he turned to Shankara and spoke in Sanskrit verses,
"Who are you asking to move aside? Are you demanding an omnipresent Self to do so or the body to do so? If you ask the body to move aside - if it is inert matter, how can it move at all?
"And how is your own body distinct and different from any other body?
"You say that you are firmly established and rooted in the Supreme Truth that there is but One non-dual Entity - One without a second. I see that you are indulging in vain pride through words of wisdom.
"Now, is there any difference between the untouchable and the Brahmin in the eye of the knower of Truth?"
On hearing these words and others too, Shankara was greatly ashamed. He clasped his palms in adoration of the man and spoke,
"He who perceives all beings with an awareness of Same-sightedness, acts in consonance with that perception of sameness in all - he indeed is my Guru. I bow down at his feet many times."
But Shankara saw something else too: A divine Being, radiant and shining like the sun and the fire, had met him in all glory, holding the four Vedas (the four dogs) in his hands.
The same episode from a remarkable old film "Adi Shankaracharya" (1983):
OM NAMAH SHIVAYA