大般涅槃經義記 6.192

6.192

念生心中，初先法說、次喻、後合。法中有二：一見生死過二乘不及，而能為生受苦不厭，故名不思；二為眾生地獄受苦如三禪樂，甘處不厭，故名不思。喻、合可知。

In the mind mindful of sentient beings, there are first the doctrinal statement, next the analogy, and then the application. In the doctrinal statement there are two points: first, seeing the faults of birth-and-death, which the two vehicles cannot match, they are nonetheless able to undergo suffering for the sake of sentient beings without wearying, hence it is called inconceivable; second, undergoing suffering in hell for the sake of sentient beings is like the bliss of the third dhyāna, which they accept contentedly without wearying, hence it is called inconceivable. The analogy and the application can be understood.