Sashti Vratam is a monthly fasting dedicated to Hindu God Muruga (Kartik) and is observed on the sixth day during the waxing phase of moon. Some devotees observe 108 Sashtis, which is for nine years. There are numerous stories regarding the origin of Sashti Vratam. This particular story is associated with Goddess Parvati and it narrates the importance of observing 108 Sashtis.
Legend has it that once Muruga wanted to know the meaning of Pranava Mantra (OM) from Brahma.
Brahma said that he is the meaning of ‘OM.’
Muruga did not like this answer and got angry and imprisoned Brahma for not properly answering his question and for belittling Pravanam.
Shiva intervened and asked Muruga why he had imprisoned Brahma. Muruga said that Brahma told him that he is the embodiment of knowledge and when asked the meaning of ‘OM’ he did not give the correct answer and this punishment is for his arrogance.
Shiva then asked Muruga to tell the meaning of ‘OM’. Muruga told Shiva that the meaning of ‘OM’ is the most guarded secret and it should only be told by a Guru to a Shishya who is ready and truly wants to learn about it.
Shiva then asked Muruga to accept him as a Shishya and tell him the meaning of ‘Om’.
Muruga then explained the importance and meaning of ‘OM’ to Shiva and thus Muruga came to known as Kumaraguru.
Muruga then felt that he did not act properly by imprisoning Brahma. For the sin committed, he took the form of a snake and started living in this form.
Goddess Parvati was unhappy with the snake form of Muruga. She complained to Shiva.
Shiva then asked Goddess Parvati to observe 108 Sashti Vratam.
When the 108 Sashtis were completed Muruga gave away the serpent form and appeared in his original form.