In Macbeth, what is one simple quote that reveals previously unknown information?
There are many quotes that might be interesting here, but I will choose the one on which the entire play seems to revolve: Macbeth finding out that Malcolm is named Duncan’s successor.
In Act 1, Macbeth and Banquo have an encounter with three witches. The witches tell them that Macbeth will be promoted twice: first to Thane of Cawdor, and then to king. Macbeth is pleased. He even writes a letter home telling his wife the good news.
Unfortunately, when Macbeth goes to Duncan, he gets some bad news. He is indeed promoted to Thane of Cawdor, as the Weird Sisters promised. He is not next in line to be king.
We will establish our estate upon
Our eldest, Malcolm, whom we name hereafter
The Prince of Cumberland; which honor must(45)
Not unaccompanied invest him only,
But signs of nobleness, like stars, shall shine
On all deservers. (Act 1, Scene 4, p. 18)
Macbeth is furious. Even though he never had any interest in being king before this, he suddenly is very angry that he was not chosen. He says that Malcolm, Duncan’s son who was chosen, is a step he must overleap or else fall down upon.
As a result of this one event, Macbeth is convinced by his wife to kill Duncan, leading to a chain of murder that does not end until Macbeth is killed.