The story of the greatness of Nandikeshvara – Shiva Purana

In the chapter 5-7 in Section 4 of Kotirudra-saṃhita of Shiva Purana, the story of greatness of Nadikeshvara is mentioned.
A noble brahmin in city named Karniki on the western bank of river Reva, born of the family of Utta, entrusted his wife to the care of his two sons and went to Kashi. The brahmin died there itself. On getting the news the two sons performed the obsequies. The wife looked after the sons, seeking their welfare. After bringing up the sons she divided the assets. She reserved some amount for her funeral expenses. After sometime when she was going to die, she made pious gifts of various sorts. Providentially she did not die. The son observing her ailments said: -
“O mother, what is amiss that you suffer so much. Please tell us so that we shall carry it out with pleasure.”
On hearing these words, she said— “There is much that is amiss. If you do the same, I shall die happily.”
The elder son replied— “Please do mention. I shall do the same.” She then replied: -
“O son, I had a great desire to go to Kashi. That was not to be. Now I am dying here. My bones shall be cast off into the waters of the Ganga assiduously. That pious act will bless you, to be sure.”
The son said: — “O mother, you shall die peacefully and with confidence. I shall carry out your task first and then attend to mine.”
After saying this, he handed water to her and went to his house. Remembering Shiva, she died in the meantime. After performing her obsequies and the monthly Shraddha he started on his journey. The elder son who was famous as Suvada took her bones and started on his pilgrimage. He engaged a servant to accompany him. He consoled his wife and sons. He performed Shraddha, Dana and other pious rites. He then set out from his house after Mangala Smarana accompanied by the servant. He walked about twelve kilometres that day and when the sun set, he halted at the house of a certain Brahmin in the auspicious village of Viṃsatigrama. He performed Sandhya and other rites duly. He recited the hymns of prayer to Shiva of wonderful activities. The brahmin stayed there accompanied by the servant. The night had passed by two muhurtas when something surprising happened.
There was a fine cow tied up in the courtyard. The brahmin of the house who had gone out returned after nightfall. On seeing the cow, tethered in the courtyard, not yet milked, the distressed brahmin desirous of milking it told his wife. In order to milk the cow, he called his wife quickly and said “O beloved, the cow is not yet milked.” Thus, urged she brought the calf. The owner of the house, dragged by the leg the calf kicked. Infuriated by the kick of the calf, he hit the calf severely with the pieces of firewood. Hit by him the calf became utterly exhausted. Due to anger neither the cow was milked nor the calf was untied by the brahmin. For the pleasure of getting milked, the cow mooed loudly. On hearing the mooing sound of the cow, the calf said: -
“O mother, why do you cry? What is the misery that has befallen you? Please tell me lovingly.” On hearing this, the cow said.
“O son, listen to me. Although I am unable to express my grief adequately, you have been hit by the wicked man. Hence, I am distressed.”
On hearing his mother’s words, the calf taking his stand by the principle of previous action replied enlightening his mother. “What should be done? Where should we go? Since the results are bound by previous actions, we experience joy or sorrow accordingly. This is a wrong notion that another man gives us sorrow or pleasure. This is also an illusory concept that it is I who do this or that. Misery or happiness results from our own actions. Hence action is prominent and everything is founded on action. All the living beings are bound by action. They are not to be bewailed by you.
On hearing these words of her calf full of wisdom, the distressed cow sorrowing for her calf, said thus. The cow said: — “O dear son, I know fully well that all the people are subservient to their actions. Still, seized by Maya I feel much distressed. I have cried a lot but the sorrow has not subsided.” On hearing these words, the calf spoke to her again. The calf said: — “If you know thus, can anything be gained by crying? Hence leave off your sorrow.”
On hearing the words of her son, the distressed cow heaved a deep sigh and spoke to the calf. The cow said: — “My distress will disappear only when a similar misery befalls the brahmin. I am telling you the truth. Tomorrow morning, I shall hit him by my horns. No doubt, when hit he will lose his life.
The calf said: — “The fruit of previous actions we experience now. What is the fruit you are going to reap as a result of this brahmin-slaughter? When merits and demerits are on a par one takes birth in Bharata. O mother, when they are wiped off by enjoyment or suffering, liberation is achieved. Sometime the action is destroyed, some time the action results. That is why you have begun to perform this misdeed. Whence am I your son? Whence are you, my mother? This fond consciousness of sonhood and motherhood is futile. Ponder. Where is mother? Where is father? Where is husband? Where is wife? Know that none belongs to anyone here. All reap the fruits of their own actions. O mother, knowing thus you cast off your misery strenuously. If there is a desire for pleasure hereafter you shall do good deeds here.”
The Cow said: — “O son, I know this but delusion does not forsake me. I am much distressed by your misery. I shall return tit for tat. I know the place that dispels the sin of brahmin-slaughter. Going there I can get rid of the sin of Brahmin-slaughter.”
On hearing these words of the mother cow, the calf observed silence. On hearing this wonderful dialogue between the two, the pilgrim brahmin was surprised and he thought within himself. “I shall leave in the morning only after seeing the wonderful sequel. I shall go to that holy spot myself.” He and his servant went to sleep. When the day dawned, the owner of the house got up. Awakening the traveller, he spoke these words. The brahmin said: --
“Why do you sleep? It is already day-break. Go on your journey to the place where you desire to go.”
He replied — “Please listen, O brahmin, there is an acute pain in the stomach of my servant. We will stay a little longer and go thereafter.” Creating such a pretext the man continued to sleep, desiring to know the details of the wonderful incident that had surprised him much.
At the time of milking, the brahmin who wanted to go somewhere on some business spoke to his son. The father said: — “O son, I am going out on some business. Dear, you shall carefully milk our cow.” After saying this, the brahmin left the house. Thereafter the son got up and untied the calf. The cow approached him herself for being milked. The brahmin’s son, eager for milk, took the distressed calf hit by his father near the cow in order to tie it up. The infuriated cow hit him with her horn. The boy, hit in a vulnerable point, fell unconscious. People gathered there, saying— “O, the boy is struck by the cow. Fetch water? fetch water?” By the time they attempted to do something, the boy died. When the boy died, there was a great hue and cry. His mother was struck with grief. She cried again and again. “What shall I do? Where shall I go? Who can remove my grief?” After lamenting thus, she struck the cow and let it off. The cow which had been white in colour turned black immediately.
On seeing this surprising event the brahmin traveller set out and followed the cow as it ran away. Lifting up its tail, the cow ran off to the river Narmada. Coming near the Nandikesha shrine, it dipped itself into the waters of the Narmada thrice. It regained its white colour and went away the way it came. The brahmin was surprised. Blessed indeed is this holy centre that removes the sin of Brahmin-slaughter. The brahmin and the servant took their baths there. After the holy dip they started on their journey praising the river. On the way they met a beautiful maiden fully bedecked in ornaments.
She said: — “O brahmin-traveller where do you go in such bewilderment? Eschewing all deceit tell me the truth here. On hearing these words, the brahmin narrated everything truthfully. The brahmin was again addressed by the women, “Stay here”.
On hearing her words, the brahmin stopped and replied humbly — “Speak out what you desire to say. She said again “In the holy spot that you have just seen, cast off the bones of your mother. Why shall you go elsewhere? Your mother will assume a divine form and will immediately attain the good goal of Shiva. In the month of Vaisakha on the auspicious seventh day in the bright half, Ganga comes here always. Today is that seventh day. The river is in the form of Ganga there.” Saying so the lady vanished. She was Ganga herself. The brahmin returned. As soon as he cast off half the bones of his mother from his bundle into the holy river, a wonderful incident happened. He saw his mother endowed with a divine form. She said — “You are blessed. You have fulfilled your duty. The family has been sanctified by you. May your wealth, food-grains, longevity and line flourish.” Blessing her son frequently, she went to heaven. With contented soul he returned to his abode.
By worshipping at Nandikesha with devotion, people become freed from all sins such as the slaughter of a Brahmin etc. At Nandikesha, Shiva appeared to save Risika, the chaste lady of a Brahmin from powerful Asura named Mudha and blessed her. Ganga also promised to stay there for a day in the month of Vaisakha.
 
Spiritual Significance:
Results are bound by previous actions; we experience joy or sorrow accordingly. This is a wrong notion that another man gives us sorrow or pleasure. This is also an illusory concept that it is I who do this or that. Misery or happiness results from our own actions. Hence action is prominent and everything is founded on action. All the living beings are bound by action. They are not to be bewailed by you.