The be all and end all
I'm Macbeth. When I'm told I'll get to be king one day, I'm just too impatient to wait. I want to wear the crown and I'll get rid of anyone who tries to take it from me. And you know what I think?
If it were done when 'tis done, then 'twere well
It were done quickly: if the assassination
Could trammel up the consequence, and catch
With his surcease success; that but this blow
Might be the be-all and the end-all here,
But here, upon this bank and shoal of time,
We'ld jump the life to come. But in these cases
We still have judgment here; that we but teach
Bloody instructions, which, being taught, return
To plague the inventor: this even-handed justice
Commends the ingredients of our poison'd chalice
To our own lips. He's here in double trust;
First, as I am his kinsman and his subject,
Strong both against the deed; then, as his host,
Who should against his murderer shut the door,
Not bear the knife myself. Besides, this Duncan
Hath borne his faculties so meek, hath been
So clear in his great office, that his virtues
Will plead like angels, trumpet-tongued, against
The deep damnation of his taking-off;
And pity, like a naked new-born babe,
Striding the blast, or heaven's cherubim, horsed
Upon the sightless couriers of the air,
Shall blow the horrid deed in every eye,
That tears shall drown the wind. I have no spur
To prick the sides of my intent, but only
Vaulting ambition, which o'erleaps itself
And falls on the other. (1.7.1-28)
Who Said It and Where
Early on in Macbeth, our leading guy (that would be Macbeth) is told he'll one day be king. He's thrilled. And confused. After all, he's not heir to the throne. And the current king isn't going anywhere. To top it all off, he's not even sure he can trust the three mysterious witches who told him this glorious news.
So he does what any other power-hungry, army-trained guy trying to prove his macho-ness would do. He takes matters into his own hands. Why sit around waiting for something when you can make it happen yourself?
But before he goes through with the deed, he does some thinking. Make that a lot of thinking. In Shakespeare's plays, we get these thoughts in the form of soliloquies. That's just a fancy word for when a character is alone on stage telling us (the audience) his thoughts.
In this soliloquy, Macbeth considers what it would actually be like to murder King Duncan and become king. And it gets a little complicated. See, if it were simply a matter of killing the king and then moving on without consequences, it wouldn't be a big issue. (Sure, what's a little murder between friends?)
Strangely, Macbeth's not worried about the murder part. He's done that in battle before. Nope, he's worried if there will be anything else he has to do later. He wonders if killing Duncan will be all that is required to end all that he must endure before he is made king. See what he did there? Be all and end all. Get it?