Karma Thubten Trinley
"These are the six syllables which prevent rebirth into the six realms of cyclic existence. It translates literally as 'OM the jewel in the lotus HUM'. OM prevents rebirth in the god realm, MA prevents rebirth in the Asura (Titan) Realm, NI prevents rebirth in the Human realm, PA prevents rebirth in the Animal realm, ME prevents rebirth in the Hungry ghost realm, and HUM prevents rebirth in the Hell realm."
Variation
The mantra: Om Mani Peme Hung Hri
As Bucknell, et al. (1986: p. 15) opine, the complete Avalokiteshvara Mantra includes a final hrīḥ (Sanskrit: ह्रीः, ), which is iconographically depicted in the central space of the syllabic mandala as seen in the ceiling decoration of the Potala Palace. The hrīḥ is not always vocalized audibly, and may be resonated "internally" or "secretly" through intentionality.
Introduction to Tibetan Buddhism
The first known citation of the mantra occurs in the Karandavyuha Sutra published in the 11th Century which appears in the Chinese Buddhist canon.[2] However, some Buddhist scholars argue that the mantra as practiced in Tibetan Buddhism was based on the Sadhanamala, a collection of sadhana published in the twelfth century.