I have taught this great auspicious mantra. Omkara came out of my mouth. Originally it indicated me.
It is the indicator and I am the indicated. This mantra is identical with me. The repetition of this mantra is verily my repeated remembrance.
By this root-mantra, the very enjoyment as well as salvation is achieved.
You shall recite as directed by the Goddess (Parvati) this Om Mantra, which is identical with me.
Your knowledge shall be stabilized. Permanent fortune shall stand by you. On the Caturdasi day and on the day with Ardra Star, the recital of this Mantra will give you ever-lasting efficacy.
Siva creates the universe at the outset saying "OM".
The Brahmin sages, the scholars, who realize and identify between the name and the sound know me as the single-syllable OM.
Then let the practitioner sitting in a retired place and restraining his senses, utter by inaudible repetition, the long pranava OM, in order to destroy all obstacles.
Letter "a" expresses Brahma, and the letter "u" Vishnu, the letter "ma" expresses Siva.
(Quoted from the Siva Parana and stated by Lord Karttikeya son of Siva).