金剛三昧經論 2.163

2.163

論曰：此下大分第三入之階位。於中有四：一明所入甚深、二舉能入位行、三者別顯階位、四者覈明入心。初中言虛空境界者，謂如如之法虛曠無相，故名虛空。內外不測者，謂內道中二十八聖及外道中九十五種，此等凡聖不能測量也。第二中言六行之士乃能知之者，是舉菩薩二入階位也。

The commentary states: Below, this is the third major section, the stages of entry. Within it there are four: first, clarifying that what is entered is extremely profound; second, citing the stages and practices of those capable of entering; third, distinctively revealing the stages; and fourth, examining and clarifying the entering mind. In the first part, stating 'the realm of space': the dharma of thusness as it is is vast, open, and signless, and is therefore called 'space'. 'Cannot be fathomed by internal or external' means that the twenty-eight kinds of noble ones within the internal teaching and the ninety-five kinds among the external paths—such ordinary beings and noble ones cannot measure it. In the second part, stating 'only persons of the six practices are able to know it' cites the stages of the bodhisattva's two entries.