Om, the mystic syllable of A-u-m is venerated by the Brahmans as well as by the Buddhists. The devotes regard it to be too sacred to be uttered aloud only formed by the lips. It is written that when all was void the triliteral syllable Aum became manifest.

Adi Budhha at his will proceeded from Om. In that Aum, Adi Buddha who is present in all things formless and passionless possesses the Tri-Ratna. It is also written that Adi Buddha became manifest in the greatest Sunyata (void) as the letter A. It is also written that when all was Sunyata, Prajna Devi (Adi Dharma) was revealed out of Akasa with the letter 'U'. The Vija mantra of Sangha is 'M'. Thus, the letters A-u-m are the vija mantra of Buddha. Dharma and Sangha V. Tri-Ratna. The mantra generally begins with Om and ends with hum, the most widely known mantra is the six syllable one of Avalokiteswara 'Om Mani Padme Hum'.