Describing about the greatness of Shadakshar mantra that consists of six letters, Suta said–
The sacred mantra — OM NAMAH SHIVAY holds a supreme place among all the mantras. During the Meghavahan kalpa of the first Treta Yuga, there lived a brahmin named Dhoondhmook. He became a licentious person due to the curse of a sage. As a result he became a man of loose moral conduct. His wife gave birth to a child on the inauspicious day of Amavasya. The astrologers predicted a very bleak future for that new born child.
When the child grew up he became notorious for his sinful conduct. Dhoondhmook married his son in a respectable family but his son being a man of loose character, developed intimacy with a woman belonging to a low caste. One day, Dhoondhmook that son developed sharp differences with that woman on some matter and in a fit of range killed her. When the family members of that woman came to know about her death, they retaliated by killing Dhoondhmook his wife and his daughter-in-law. Since Dhoondhmook’s son was not present in the house at that time he survived. He avenged the death of his family members by killing the assasins. Now Dhoondhmook’s son had become disillusioned with life. He started wandering aimlessly and reached a hermitage. The sage who lived in that hermitage was a great devotee of Lord Shiva and taught him the rituals of Pashupat Vrata as well as the sacred Shodakshar mantra. Dhoondhmook’s son performed the rituals of Pashupat Vrat for twelve months. All the while he kept on chanting the Shadakshar mantra. As the result of his devotion towards Lord Shiva and by the virtue of chanting Sadakshar mantra he as well as all his ancestors attained salvation.