Those who desire liberation strive to comprehend the Great Middle Way of perfect truth, which is free from extremes of exaggeration and denigration. How is it comprehended? The Buddha Nature that exists as the ground is like a wish-fulfilling jewel covered by the mud of the stains.
Cleansing it with the stream of the view, meditation, and conduct causes the result of the reality body (dharmakaya) endowed with twofold purity, which is like the jewel without stains, to actualize, and everything meaningful for oneself and others is spontaneously present.
While the ground Buddha Nature of the reality body (dharmakaya) and the resultant Buddha Nature of the reality body (dharmakaya) have not the slightest difference in essence, they are distinguished as ground and result by means of the presence or absence of incidental stains. This is like referring to the space of the sky in situations when it is free or not free of clouds.
—Kunchen Dolpopa, An Instruction