Perchance he for whom this bell tolls may be so ill, as that he knows not it tolls for him; and perchance I may think myself so much better than I am, as that they who are about me, and see my state, may have caused it to toll for me, and I know not that.
tolled to let them know your ill not dead
Ask not for whom the bell tolls; it tolls for thee. They used to ring the bell to let people know that somebody died, but the point of the quote was that it didn't toll for the person who died, since he wouldn't here it anyway; it tolled for us, so that we would know that someone had died.