Personally I think the beginning is very interesting and explains the name of the movie very well

The first part:

lt; Nirvana Sutra gt; Volume 19;" The most of the eight hells is called the endless hell. It means suffering great suffering without interruption."

Hence the name.

End:

Buddha said: Those who receive the Infinite Body will never die, and longevity is the great calamity in the Infinite Hell.

Part Three:

End:

The Original Sutra of Ksitigarbha Bodhisattva Above: People like this will fall into the endless hell for tens of millions of kalpas, hoping that there will be no escape.