Shakespearean themes are evident in the novel in subtle ways. There is an unseen power (government controlling the city); brother betrays brother in hiding books (Mildred informs on Montag); a jester offers commentary (the White Clown, symbolizing the meaningless emotion of television); an old person offers predictions and pronouncements (Faber, explaining the state of the world); characters suffer from madness (Montag has fits of delirium and rage from his conflicting emotions). One of the most important references comes at the end, when Montag confronts Beatty for the last time:
"Speech away[, Beatty said.] What'll it be this time? Why don't you belch Shakespeare at me, you fumbling snob? 'There is no terror, Cassius, in your threats, for I am arm'd so strong in honesty that they pass by me as an idle wind, which I respect not!' How's that?"
(Bradbury, Fahrenheit 451, Google Books)
The quote is from Julius Caesar, where Brutus explains to Cassius that his threats are meaningless because he, Brutus, is armed with honesty; even if he is killed, people will take up his cause and avenge him. Beatty believes in his cause, that the government should control the life of every individual, so he claims to have no fear of death. Montag obliges.
One of the main themes throughout Fahrenheit 451 concerns the censorship of literature. Arguably the most important and talented English literary figure in history is William Shakespeare. His contributions to the English language are unrivaled by any other literary figure, and he is considered the world's pre-eminent dramatist. Shakespeare's work encapsulates nearly every human emotion and is associated with various scenes and subjects throughout the novel. Bradbury alludes to Shakespeare multiple times throughout the novel to provide context to the characters' situations while simultaneously connecting them to the theme of censorship.
In Montag's final interaction with Beatty, Beatty alludes to Shakespeare multiple times by telling Montag, "Truth is truth, to the end of reckoning," which is a line from Act Five, Scene One of Shakespeare's play Measure for Measure.
Beatty also quotes Shakespeare's Merchant of Venice by telling Montag, "Truth will come to light, murder will not be hid long!...Oh God, he speaks only of his horse!...The Devil can cite Scripture for his purpose" (Bradbury, 51).
Before Montag shoots Beatty with his flamethrower, Beatty quotes Brutus from Julius Caesar by saying, "There is no terror, Cassius, in your threats, for I am arm'd so strong in honesty that they pass by me as an idle wind, which I respect not!" (Shakespeare, 4.3.70-73).
Each quote from Shakespeare becomes part of Beatty's argument and reveals the breadth of Shakespeare's literary genius. Interestingly, Beatty's use of Shakespeare seems to supports Montag's cause and not his own.