Duncan's Arrival
In Act One, when King Duncan arrives at Macbeth's castle, he says, "This castle hath a pleasant seat" (1.6). This statement is an example of verbal irony because, though Duncan feels welcome and comfortable in the castle, the audience knows it will soon be the setting for his murder.
Macbeth's News
After murdering Duncan, Macbeth informs Malcom and Donalbain of their father's death, saying, "The spring, the head, the fountain of your blood / Is stopped; the very source of it is stopped" (2.3). Here, Macbeth appears aggrieved and shocked by Duncan's death, but in actuality is the very murderer who took the king's life.
Lady Macbeth
Lady's Macbeth's incessant washing of her hands represents a moment of dramatic irony in the play. While the other characters in the scene assume she has simply gone mad, the audience knows that her behavior stems from her own sense of guilt over having taken part in Duncan's murder.
Macduff
The witches prophecy that Macbeth will become king and will not be overthrown by any man "of woman born" (4.1). Their prophecy leaves little doubt over Macbeth's continued rule, but the audience knows that Macbeth is a tragedy and that the lead character will soon fall. The witches' prophecy therefore represents a moment of situational irony, as the audience knows that their prediction will in some way be challenged, despite not knowing how (eventually, the audience will learn that Macduff was born by Caesarian section, and therefore not "of woman").
