大般涅槃經義記 6.201

6.201

第五段中辯明菩薩行業清淨，在生死中不為其害，是故不思，先喻、後合。

In the fifth section, it explains that the bodhisattva's actions and karma are pure, and while in birth-and-death they are not harmed by it; for this reason it is inconceivable, first with the analogy and then the application.