The passage in question describes an iron ball that has been heated all day such that it becomes more light, soft, workable, and luminous. Similar to the condition of such a heated iron ball, as a result of engaging in a certain meditation practice the Buddha’s body becomes more light, soft, workable, and luminous. No parallel to this discourse is known to me, wherefore nothing further can be said from a comparative perspective.

Nevertheless, in relation to my present topic I would like to note that for the Buddha’s body to become “more luminous”, pabhassarataro, at least as long as the term is understood in a visible sense,38 seems less straightforward than for the same to be said of a heated iron ball. This is not to deny that in describing the mind a metaphor has its place or that meditation practice can have visible effects on the body. My point is only that when iron is heated up, it will indeed emit light, whereas for a comparable effect to happen with the human body of someone immersed in meditation is considerably less self-evident.

《解脱道论》卷9〈五通品 9〉：“彼坐禅人修四如意足。以作自在心。其身随心其心成随身。彼坐禅人于时安身。于心安心于身。以由身心变。以由心身变。以由身心受持。以由心身受持。或乐想或轻想着于身。于著成住。彼坐禅人如是现修成最轻。其身成最软最堪受持。如铁丸为火所烧随意作物。如是以修心成身轻。以轻故入第四禅。安详念出能分别虚空。以智受持。如是于虚空此身当起。以智受持。于虚空成起。如风吹绵缕。”(CBETA, T32, no. 1648, p. 442, a6-15)