Hara Hara Mahadeva Shambho Shankara
Why is God Shiva worshipped in the Linga form in Sanatana Dharma?
According to Padma Purana :: One day Sage Bhrigu plans to visit the Tridev(Lord Brahma, Vishnu and Shiva) as he wanted to declare the best among the Tridev to the entire Universe. With this thought he goes first to Lord Brahma (Brahma lok), but he observes that Brahma was too busy in his creation and turns a blind eye towards Sage Bhrigu. This angers the sage and he curses Brahma from being worshipped in the world
- Next he proceeds towards Mount Khailash to visit Shiva and Goddess Parvathi. Before he could enter into Khailash, the sage is stopped at the entrance gate by Nandi, Shiva's mount. Sage Bhrigu says, “I want to visit Shiva, allow me in”.
- Nandi says, “Hey Sage, I'm sorry I can't allow you inside. Since Shiva and Goddess Parvathi are in their private chamber, you should wait for some time”.
- This angers Sage Bhrigu, and He curses Shiva, “Hey Mahadeva, you are too busy in your private life because of your beauty. I here by curse you, from today onwards you shall be worshipped in the form of pashaan (Stone). So, from that day onwards, Shiva is being worshipped in Linga or stone form.

According to Shiva Purana ::
When Lord Brahma and Shri Vishnu were fighting among themselves over supremacy, then God Shiva transformed Himself into a column of fire or Shivalinga and asked them to find the aadi(start) and Anth(end) of the Linga. Both Shri Vishnu and Brahma couldn’t find the start and end of that pillar, and they revered Him as God of the God’s(Mahadev) and from that day onwards God Shiva is worshipped in the Linga form.