[344] "And what, friends, is the fire element (tejodhātu)? The fire element may be internal, or it may be external. And what, friends, is the internal fire element? Whatever internally, belonging to oneself, is fire, fiery, and appropriated (upādinna), namely: that by which one is warmed, that by which one ages, that by which one is consumed with fever, and that by which what is eaten, drunk, chewed, and tasted comes to full digestion; or whatever else internally, belonging to oneself, is fire, fiery, and appropriated — this, friends, is called the internal fire element. Now both the internal fire element and the external fire element are simply the fire element (dhātu). That should be seen as it really is with right wisdom thus: 'This is not mine, this I am not, this is not my self.' Having seen it thus as it really is with right wisdom, one becomes disenchanted with the fire element and makes the mind dispassionate toward the fire element.
There comes a time, friends, when the external fire element is agitated. It burns up a village, burns up a city, burns up a market town, burns up a district, burns up a region of a district. Coming to the edge of green grass, or the edge of a road, or the edge of rock, or the edge of water, or a delightful stretch of ground, it is extinguished for lack of fuel. There comes a time, friends, when people seek fire even with a cock's feather or a shred of sinew. So then, friends, since even of this external fire element, great as it is, the impermanence will be evident, the nature to be destroyed will be evident, the nature to vanish will be evident, the nature to change will be evident — what, then, of this body, lasting but a little while, appropriated by craving (taṇhā), that it should be regarded as 'I' or 'mine' or 'I am'? Rather, there is for him here no such regard at all.
Friends, if, when that bhikkhu thus recollects the Buddha, thus recollects the Dhamma, thus recollects the Saṅgha, equanimity supported by the wholesome becomes established, he is pleased on that account. Friends, even to this extent, much has been done by that bhikkhu."
English translation from the Pali (Siam Raṭṭha edition) — under review, not for citation.