金剛經纂要刊定記 5.131

5.131

依此下。結成疑也。謂依此經受持解說不憚勞苦，即是菩薩行。菩薩之行無所不為，剜身然燈割股救鴿，一句投火半偈亡軀，供佛燒身捐形飼虎，如是等行皆名苦因。為行頗同果證何異，因果既等何勝劣哉？

"Relying on this...", etc., formulates the doubt. It means that relying on this sūtra to uphold and explain it without shunning toil and suffering is precisely the bodhisattva's practice. In the bodhisattva's practice there is nothing they will not do: gouging one's flesh to burn lamps, slicing one's thigh to rescue a dove, leaping into fire for a single line, giving up one's life for half a verse, burning one's body to make offerings to the Buddha, and renouncing one's form to feed a tiger. Practices such as these are all termed causes of suffering. Since their practice is quite the same, how could their fruition and realization differ? When cause and fruition are both equal, what superiority or inferiority could there be?