Nag panchami vrat katha or the story associated with it is given here. During the Sarpayaga of King Janamejaya, the entire clan of Serpents was destroyed. Some Serpents went to Lord Brahma and expressed their concern about the existence of Sarpa clan. Brahma consoled them and gave a boon that they will be worshipped as Gods in the earth with the help of a great man called ‘Asthika’. That was Shukla Paksha Panchami in Shravan month hence since then observing Naga Panchami puja on this day has become auspicious & meritorious.
The importance of Naga Puja is mentioned in Vrata Chudamani in Prabhasa Khanda of the Skanda Purana & Bhavishya Uttara Purana.
Nag Panchami Vrat katha is mentiobed in Bhavishyottara Purana as a conversation between Lord Shiva and Goddess Parvati. The story goes like this…
Once upon time, a farmer was digging in his field. When he dug near a tree, unknowingly he hit a baby of a snake and it was died on the spot. Mother of the baby snake became furious and bit the farmer and his all family members and killed them all. Enraged snake’s anger not decreased then and wanted to kill the farmer’s daughter also who lives in neighboring village. When the snake entered into her house, she was performing Naga puja. Seeing this, snake’s anger was pleased and by the wish of farmer’s daughter she made all the members of farmer’s family alive.
This concludes the story of Naga Panchami. It explains that Naga puja will make us, our family, and our next generations to live with happiness and prosperity.
It is to note that in 2016, Naga Panchami date is August 7.