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.

《解脫道論》卷9〈五通品 9〉：「彼坐禪人修四如意足。以作自在心。其身隨心其心成隨身。彼坐禪人於時安身。於心安心於身。以由身心變。以由心身變。以由身心受持。以由心身受持。或樂想或輕想著於身。於著成住。彼坐禪人如是現修成最輕。其身成最軟最堪受持。如鐵丸為火所燒隨意作物。如是以修心成身輕。以輕故入第四禪。安詳念出能分別虛空。以智受持。如是於虛空此身當起。以智受持。於虛空成起。如風吹綿縷。」(CBETA, T32, no. 1648, p. 442, a6-15)