What are the origins of this quote? (referred in Akuma No Riddle)

The problem here is that you would most likely need to know the sentence in Japanese to look it up more specified since every fansub-group out there could interpret the sentence in a different way (and therefore the sentence could be different as well). Maybe some Japanese said it in Japanese, but yeah, that's the problem with different languages ... each and everyone translates something in a different way. And maybe there's an english quote like that (just with other words but with the same meaning), but I haven't found out anything.

Maybe you can ask the fansub-group directly :D

I remember searching for the quote too, give me a while and I'll post the quote as it was said in the episode in Japanese and maybe you can do some research (or anyone else that chances upon this thread)

EDIT: Here's that line

死は人生の終末ではない、生涯の完成である
(Shi wa jinsei no shuumatsu dewa nai, shougai no kansei de aru)