[117] Therein, what is the fire element (tejodhātu)?
The fire element is twofold: there is the internal, there is the external.
Therein, what is the internal fire element? That which internally, belonging to oneself, is fire, what is fiery; heat, what is hot; warmth, what is warm — internal, clung-to (upādinna) — namely: that by which one is heated, that by which one ages, that by which one is burned up, and that by which what is eaten, drunk, chewed, and tasted becomes completely digested; or whatever else there is internally, belonging to oneself, that is fire, what is fiery; heat, what is hot; warmth, what is warm — internal, clung-to: this is called the internal fire element.
Therein, what is the external fire element? That which externally is fire, what is fiery; heat, what is hot; warmth, what is warm — external, not clung-to (anupādinna) — namely: a wood fire, a fire of splinters, a grass fire, a cow-dung fire, a chaff fire, a rubbish fire, lightning fire; the heat of fire, the heat of the sun, the heat of a heap of wood, the heat of a heap of grass, the heat of a heap of grain, the heat of a heap of ashes; or whatever else there is externally that is fire, what is fiery; heat, what is hot; warmth, what is warm — external, not clung-to: this is called the external fire element.
The internal fire element and the external fire element — having gathered them together and combined them as one — this is called the fire element.
English translation from the Pali (Siam Raṭṭha edition) — under review, not for citation.