大方廣佛華嚴經疏 42.15

42.15

八知虛空身，文有六相：一無量相，芥子中空亦無分量故。二遍至一切色非色處故。三不可見故。今世人見者，但見空一顯色想心謂見，故《涅槃經》中廣破見空。又此含無為空故，亦不可見。四無異相者，無障礙故，謂不同色法，彼此相異有障礙故。五無為相，謂無始終起盡之邊故。六能通受色相持所持故。故下經云「譬如虛空寬廣非色，而能顯現一切諸色。」既因色分別彼是虛空，則知因空顯彼為色。

Eighth, knowing the space body. The text has six marks: First, the mark of immeasurability, because even the space within a mustard seed has no measurable dimension. Second, because it pervades all material and non-material places. Third, because it cannot be seen. When people of the world see it nowadays, they merely see the conceived perception of the single manifest color of space and think they see it; hence in the Nirvāṇa Sūtra, seeing space is extensively refuted. Furthermore, because this contains the unconditioned space, it is also invisible. Fourth, the mark of non-difference, because it is unobstructed; that is to say, unlike material dharmas, which differ from one another and present obstructions. Fifth, the mark of being unconditioned, meaning it has no margins of beginning or end, arising or ceasing. Sixth, being able to universally receive material marks, sustaining what is sustained. Hence a subsequent chapter of the sūtra states: 'Just as empty space is vast and non-material, yet able to manifest all material forms.' Since it is through matter that one distinguishes that as empty space, one then knows that it is through space that that is revealed as matter.