What are some examples of tyranny in Macbeth?Are there any important tyrannical quotes?

Certainly there are many acts of tyranny in
Macbeth.  Macbeth likes the power that he has and he is driven by
his fear that someone will find out that he is guilty of the murder of King Duncan (and
later others).  As a result, Macbeth's behavior becomes increasingly tyrannical; for
example, in Act 4, Macbeth decides to have Macduff's family murdered because he thinks
that Macduff suspects him of foul play.  Macbeth sends his men to murder everyone in the
castle including Macduff's wife and son.  This act of tyranny drives Lady Macbeth over
the edge when she reflects on the fact that Lady Macduff and her son where completely
innocent and did not deserve the brutality inflicted on them.