What does the knell and h**l part of macbeth mean?

Question

HELP!!

" I go, and it is done; the bell invites me.

Hear it not, Duncan, for it is a knell

That summons thee to heaven, or to h**l. "

Answer 1

Macbeth is about to murder Duncan.  He hears the knell of the bell which marks the time and he imagines he is speaking to Duncan, who is not present (a technique called apostrophe).  He tells the imagined Duncan not to hear the bell for it is the sound that will mark his death and thus send him to either heaven or h**l.