金剛經纂要刊定記 3.121

3.121

無我下。出忍之所以也。斯有兩意，所謂通別。通則由無我相，雖累遭割截常能忍受。別則由無我故能忍，由累苦故能忍也。

From "no self..." downward, it explains the reason for forbearance. This has two senses, namely general and specific. Generally, because of the absence of the mark of a self, even when repeatedly subjected to dismemberment, one can always endure it. Specifically, it is because there is no self that one can endure, and it is on account of repeated suffering that one can endure.