"Question: If the entity of all living beings is the Mystic Law in its entirety, then are all the actions and their results that are associated with the nine worlds, from the world of hell up to that of bodhisattvas, in effect entities of the Mystic Law?
Answer: The mystic principle that is the essential nature of phenomena possesses two aspects, the defiled aspect and the pure aspect. If the defiled aspect is operative, this is called delusion. If the pure aspect is operative, this is called enlightenment. Enlightenment constitutes the realm of Buddhahood. Delusion constitutes the realms of ordinary mortals.
These two aspects, the deluded and the enlightened, are indeed two different phenomena, and yet both are workings of the one principle, that is, the essential nature of phenomena, or the true aspect of reality. It is like a piece of crystal. If the crystal is placed in the sun’s rays, it will attract them and produce fire. But if it is placed in the moon’s rays, it will produce water. The crystal is a single entity, but the effects it produces differ according to the circumstances.
The mystic principle of the true aspect of reality is like this. The mystic principle of the true aspect of reality is one, but if it encounters evil influences, it will manifest delusion, while if it encounters good influences, it will manifest enlightenment. Enlightenment means enlightenment to the essential nature of phenomena, and delusion, ignorance of it."
-From "The Entity of the Mystic Law," a missive of Nichiren Daishonin to his disciple Sairen-bo, perhaps 1273