金剛三昧經論 2.117

2.117

論曰：言實際者，離虛之稱、究竟之義，離幻究竟故名實際。依教修理，理入行入，故名為入。然實際以無際為際，二入是無入之入，故名〈入實際品〉。

The treatise states: Regarding "reality-limit": it is a designation for being free from falsehood and has the meaning of the ultimate; being free from illusion and being ultimate, it is called the "reality-limit." Cultivating the principle relying on the teaching, there is entering through principle and entering through practice; hence it is called "entering." However, the reality-limit takes the limitlessness as its limit, and the two entries are entries of non-entering; hence it is called "Chapter on Entering the Reality-Limit."