We couldn't help it. We just had to take a peek at the ending of the play. Here's what goes down, in case you haven't finished reading the play yet.
Macbeth is slain by Macduff, who lops off Macbeth's head and presents it to Malcolm, the soon to be crowned king. (What? You were expecting something else? This is a Shakespearean tragedy, so it's got to end with a little blood and death, right?)
The thing is, though, Shakespeare's tragedies are also always interested in reestablishing a sense of political order and continuity. So, while Macbeth has been running amok throughout the entire play (killing kings, ordering the murders of children, hanging out with witches, and putting his own selfish needs before the good of the kingdom), we're left with a sense that Malcolm's rule will be a time of healing and restoration…or will it?
After Macbeth's severed head is delivered to the soon-to-be-king, everyone in the vicinity yells out "Hail, King of Scotland" (5.11). Now, where have we heard that before? Oh, we know, that's what the witches call out to Macbeth at the play's beginning, just before all hell breaks loose. You might want to revisit Act I, scene iii, where Macbeth first encounters the weird sisters. We counted, and the witches say "hail" to Macbeth no less than ten times – that word is a loud and creepy echo by the time they're done with it. We can't help but wonder if Malcolm, who is enthusiastically "hailed" as King of Scotland, will be a good ruler or, if he'll turn out to be just as oppressive as Macbeth. This move is pretty typical of Shakespeare. Big Willy always likes to leave us guessing.