All beings have buddha nature. . . . When this point has been well understood, the Bodhisattva will give rise to a heroic and greatly courageous mind.

It is only on the basis of this heroic mind that the practice of deity yoga can flourish. Through meditating on the deity, one purifies the inner physical propensities accumulated since time without beginning. As a result, imprints regarding outer forms will be cleansed. Through mantra recitation, one purifies the inner propensities of speech. As a result, imprints related to outer sounds will be cleansed. Finally, through continually cultivating bodhicitta, one purifies self-grasping. In this way, even an hour of sadhana practice clears away obscurations of body, speech, and mind.

-- Garchen Rinpoche