Story behind this fast
According to the legend of this fast, once in a town named Kaudinya, a Brahmin named Vamana and his wife named Satya. Both lived with love in their hut i.e. their house, there was no shortage of any kind in their house, but both of them used to be unhappy because they did not have children.
One day Narad ji came to his house, Brahmin and his wife served Narada Muni with reverence and asked some solution to get their child.
Narad Muni also understood that both husband and wife were very sad, then they only told that there is a forest at some distance from your house, at the southern end of it, under a bilva tree with Lord Shiva and mother Parvati. He resides in the form of a linga. You both can Worship him, he will be the solution to all your sorrows.
Then the Brahmin husband and wife found that Shivling, cleaned it and started worshiping according to the law. Similarly, he spent about 5 years in worship.
It is a matter of one day, when the Brahmin was plucking flowers for his worship, suddenly a snake came and bitten the Brahmin, he fell into the forest when the husband did not reach home even after a long time, his wife Seeing her husband who had reached the forest in search of him, she started crying a lot, she started calling mother Parvati and the forest deity.
Hearing the call of the wife, the forest deity and mother Parvati came and put nectar in the head of the Brahmin, due to which the Brahmin was resurrected, Mother Parvati was not pleased with his worship, she asked the couple what they wanted to ask, then both of them expressed desire to get children. Mother Parvati suggested them to observe Vijaya Parvati fast.
On the day of Ashadh Shukla Trayodashi, both the Brahmin couple completed this fast of Mother Parvati with the rituals, due to which they got a son, so whoever observes the fast on this day with full devotion, can get a child and his/her good fortune remains forever.
Sawan Shiv puja: Worship Devadhidev Mahadev with these mantras in Sawan, know 108 names of Lord Shiva
