About Om mani padme hum
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The six syllables, om mani padme hum, mean that in dependence on the practice of a path which is an indivisible union of method and wisdom, you can transform your impure body, speech, and mind into the pure exalted body, speech, and mind of a Buddha.
The six-syllabled Sanskrit mantra is associated with the four-armed Shadakshari form of Avalokiteshvara, the bodhisattva of compassion.
It first appeared in the Mahayana Kāraṇḍavyūhasūtra where it is also referred to as the sadaksara (six syllabled) and the paramahrdaya.