What are some significant quotes from Macbeth that result in significant consequences for the speaker and others?I have a five minute speech due....

I think this is an interesting assignment, so have fun
with it!  I would suggest looking at Lady Macbeth.  She has a very important speech in
Act I, Scene v, in which she decides that Duncan will be murdered while he is a guest in
her home and that Macbeth will be convinced (against his better nature?) to commit the
act.

She also calls on what appear to be forces of evil to
assist her scheme.  It could be said that not only do these forces of evil assist Lady
M, but that they take over the heart and mind of Macbeth too.  Pretty significant
consequences (the death of King Duncan) that affect everyone in the play
Macbeth.

Here's the
quote:

The
raven himself is hoarse

That croaks the fatal entrance of
Duncan

Under my battlements.  Come you
spirits

That tend on mortal thoughts, unsex me
here,

And fill me from the crown to the toe
top-full

Of direst cruelty!  Make thick my
blood;

Stop up the access and passage to
remorse,

That no compunctious visitings of
nature

Shake my fell purpose, nor keep peace
between

The effect and
it!

Good luck with your
speech!