The fire element comes from the tathāgatagarbha
In the Śūraṅgama Sūtra, the Buddha said that fire comes from the tathāgatagarbha and is the nature of the tathāgatagarbha. But there is nothing at all within the tathāgatagarbha—no shape, no marks, no hardness, no heat, no wateriness, no drifting motion; He does not even have a material appearance as tiny as a speck of dust. Yet He can manifest the trichiliocosm of the ten directions—how utterly inconceivable. Therefore, when one studies the Buddha-dharma to the very end and comes to know the real nature of all dharmadhātus, no longer deluded or confused, one will perfectly accomplish the Buddha Way.
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