Om Nani Padme Hum is a sacred mantra in Mahayana Buddhism.
H.H. The Dalai Lama has explained that "...the six syllables, Om Ma-ni Pad-me Hum, mean that in dependence on the practice which is in indivisible union of method and wisdom, you can transform your impure body, speech and mind into the pure body, speech, and mind of a Buddha."
Om Mani Padme Hum in Tibetan
Chenrezig is the archangelic Bodhisattva of Great Compassion. Also known as Avalokiteshvara, his vast vows to save all beings are said to be inconceivable. With his special mantra, Om Mani Padme Hum, he travels to all the realms of the universe in his tireless quest to deliver beings from suffering.
Here is a video clip with Tibetan chanting of the mantra, Om Ma Ni Pe Me Hung.
This is the Om Mani Padme Hum mantra in Chinese:
Ăn Má Ní Bā Mī Hōng
Download the Chinese chant here.
Painting: Om Mani Padme Hum, by Karma Phuntsok.