Macbeth

by

William Shakespeare

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Macbeth: Irony 9 key examples

Read our modern English translation.
Definition of Irony
Irony is a literary device or event in which how things seem to be is in fact very different from how they actually are. If this seems like a loose definition... read full definition
Irony is a literary device or event in which how things seem to be is in fact very different from how they actually are. If this... read full definition
Irony is a literary device or event in which how things seem to be is in fact very different from how... read full definition
Act 1, scene 4
Explanation and Analysis—Life and Death:

In Act 1, Scene 4, Malcolm describes the Thane of Cawdor's execution:

Malcolm: [V]ery frankly he confessed his treasons,
Implored your Highness' pardon, and set forth
A deep repentance. Nothing in his life
Became him like the leaving it.

This moment is ironic for a few reasons. The Thane of Cawdor never physically appears in the play, and the few times he is mentioned, he is described as a rebellious traitor, so it is ironic that Malcolm characterizes his behavior prior to the execution as honest and repentant—in death, he behaves more nobly than he ever did in life.

Malcolm's remark that dying is the worthiest deed the Thane of Cawdor ever did may also be a reference to his overall role in the play's narrative. It is the treachery and subsequent death of the Thane of Cawdor that fulfills the first part of the Weird Sisters' prophecy and sets the events of the play in motion. The Thane of Cawdor is less of a character than he is a plot device—if he did not betray Duncan and was not executed, he would serve no function in the play. In other words, Shakespeare brought this character to life with the sole intention of killing him.

Act 1, scene 5
Explanation and Analysis—False Appearances:

When the Weird Sisters speak their famous line—"Fair is foul and foul is fair"—in Act 1, Scene 1, they introduce the idea that not everything in Scotland is as it seems. This motif of false and deceptive appearances persists throughout Macbeth, and the tension between how things appear and how they really are means that the play is often deeply ironic.

In Act 2, Scene 4, Duncan laments the fact that one cannot divine a person's intentions just by looking at them:

Duncan: There’s no art
To find the mind’s construction in the face.

The Thane of Cawdor appeared to be an honorable and loyal thane, but this appearance disguised a traitorous nature.

In Act 1, Scene 5, Lady Macbeth chastises Macbeth for his expression, which betrays his thoughts, and counsels him to play the part of the gracious host:

Lady Macbeth: Your face, my thane, is as a book where men
May read strange matters. To beguile the time,
Look like the time. Bear welcome in your eye,
Your hand, your tongue. Look like th’ innocent
    flower,
But be the serpent under ’t.

Just as the "pleasant seat" of Inverness conceals the devious machinations of its mistress, Macbeth's welcoming behavior disguises his murderous intentions.

In Act 1, Scene 7, Lady Macbeth further instructs her husband to make a spectacle of his grief following Duncan's murder so that no one will suspect that he is responsible:

Lady Macbeth: Who dares receive it other,
As we shall make our griefs and clamor roar
Upon his death?

Macbeth responds with a play on the word "false," which can be synonymous with "dishonest" in the sense of a fake or artificial appearance or in the sense of a treacherous heart: 

Macbeth: Away, and mock the time with fairest show.
False face must hide what the false heart doth
    know.

In Act 2, Scene 3, following the discovery of Duncan's murder, Malcolm correctly observes that one or more of the thanes may be faking his grief:

Malcolm: To show an unfelt sorrow is an office
Which the false man does easy

In response, Donalbain expresses concern that he and his brother are no longer safe in Scotland, noting that the pretense of loyalty can hide treacherous intentions:

Donalbain: Where we are,
There’s daggers in men’s smiles.

Later on in the play, Macbeth and Lady Macbeth struggle to conceal their guilt and paranoia. In Act 3, Scene 2, they encourage each other to put on a show for the visiting thanes:

Lady Macbeth: Sleek o’er your rugged looks. Be bright and jovial
Among your guests tonight.

Macbeth: So shall I, love,
And so I pray be you. Let your remembrance
Apply to Banquo; present him eminence
Both with eye and tongue: unsafe the while that we
Must lave our honors in these flattering streams
And make our faces vizards to our hearts,
Disguising what they are.

By the end of the play, all these false appearances have fallen apart. Just as the Thane of Cawdor's treachery eventually came to light, Macbeth and Lady Macbeth's crimes are revealed, and they are punished for their duplicity.

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Act 1, scene 6
Explanation and Analysis—Delicate Air:

In Act 1, Scene 6, Shakespeare employs olfactory imagery to describe Macbeth's castle at Inverness. Duncan and Banquo, oblivious to the fact that the castle will soon become the site of a violent murder, comment on the excellent quality of the air:

Duncan: This castle hath a pleasant seat. The air
Nimbly and sweetly recommends itself
Unto our gentle senses.

Banquo: This guest of summer,
The temple-haunting martlet, does approve,
By his loved mansionry, that the heaven’s breath
Smells wooingly here. No jutty, frieze,
Buttress, nor coign of vantage, but this bird
Hath made his pendant bed and procreant cradle.
Where they most breed and haunt, I have
    observed,
The air is delicate.

This passage is highly ironic, since the pleasant odor that Duncan and Banquo spend so much time discussing is later replaced by the stench of blood. In what may be a subtle instance of foreshadowing, their commentary contrasts sharply with Lady Macbeth's line in Act 5, Scene 1:

Lady Macbeth: Here’s the smell of the blood still. All
the perfumes of Arabia will not sweeten this little
hand.

It is also ironic that so many martlets have decided to build their nests in the walls of Macbeth's castle. Martlets, also called martins, are small birds in the swallow family that often roost in the walls of tall buildings or, as Banquo mentions, in church steeples. The presence of these church-dwelling birds, along with Banquo's use of the phrase "heaven's breath" gives the atmosphere of Inverness a holy quality. This sacred appearance is especially ironic given the fact that, in the previous scene, Lady Macbeth encouraged her husband to "Look like the innocent flower, / But be the serpent under it"—that is, to behave like the treacherous snake in the Garden of Eden.

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Act 1, scene 7
Explanation and Analysis—Duncan's Murder:

The discovery of Duncan's murder in Act 2, Scene 3 is an extended moment of dramatic irony. The audience is aware that Duncan is dead, but Macduff and Lennox are oblivious, an ignorance that Macbeth maintains by making comments that imply the king is still alive.

Lennox: Goes the king hence today?

Macbeth: He does. He did appoint so.

The audience knows that Macbeth is responsible for the murder, but when Macduff announces that Duncan is dead, Macbeth feigns surprise:

Macbeth and Lennox: What's the matter?

Macduff: Confusion now hath made his masterpiece.
Most sacrilegious murder hath broke ope
The Lord’s anointed temple and stole thence
The life o’ th’ building.

Macbeth: What is 't you say? The life?

When Lady Macbeth arrives on the scene, Macduff initially refuses to tell her what has happened, fearing that the news will devastate her feminine sensibilities:

Macduff: O gentle lady,
’Tis not for you to hear what I can speak.
The repetition in a woman’s ear
Would murder as it fell.

This concern is highly ironic, since Lady Macbeth was the one who planned and assisted with the killing of Duncan. In Act 1, Scene 7, she even questioned her husband's manhood when he proved reluctant to carry out the crime:

Lady Macbeth: Who dares receive it other,
As we shall make our griefs and clamor roar
Upon his death?

In the same scene, Macbeth and Lady Macbeth plan how they will pretend to react to news of Duncan's death with grief and horror:

Lady Macbeth: Who dares receive it other,
As we shall make our griefs and clamor roar
Upon his death?

As a result, in Act 2, Scene 3, the audience sees through Lady Macbeth's swooning and Macbeth's explanation for killing Duncan's guards:

Macbeth: O, yet I do repent me of my fury,
That I did kill them.

Macduff: Wherefore did you so?

Macbeth: Who can be wise, amazed, temp’rate, and furious,
Loyal, and neutral, in a moment? No man.
Th’ expedition of my violent love
Outrun the pauser, reason. [...]

In this passage, Macbeth tries to suggest that he flew into a "violent" passion that overtook his ability to see "reason." So although the other thanes believe him when he claims to have murdered the guards out of a sense of rage and loyalty, the audience knows that he did it to conceal evidence of his own crime—creating yet another instance of dramatic irony.

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Explanation and Analysis—False Appearances:

When the Weird Sisters speak their famous line—"Fair is foul and foul is fair"—in Act 1, Scene 1, they introduce the idea that not everything in Scotland is as it seems. This motif of false and deceptive appearances persists throughout Macbeth, and the tension between how things appear and how they really are means that the play is often deeply ironic.

In Act 2, Scene 4, Duncan laments the fact that one cannot divine a person's intentions just by looking at them:

Duncan: There’s no art
To find the mind’s construction in the face.

The Thane of Cawdor appeared to be an honorable and loyal thane, but this appearance disguised a traitorous nature.

In Act 1, Scene 5, Lady Macbeth chastises Macbeth for his expression, which betrays his thoughts, and counsels him to play the part of the gracious host:

Lady Macbeth: Your face, my thane, is as a book where men
May read strange matters. To beguile the time,
Look like the time. Bear welcome in your eye,
Your hand, your tongue. Look like th’ innocent
    flower,
But be the serpent under ’t.

Just as the "pleasant seat" of Inverness conceals the devious machinations of its mistress, Macbeth's welcoming behavior disguises his murderous intentions.

In Act 1, Scene 7, Lady Macbeth further instructs her husband to make a spectacle of his grief following Duncan's murder so that no one will suspect that he is responsible:

Lady Macbeth: Who dares receive it other,
As we shall make our griefs and clamor roar
Upon his death?

Macbeth responds with a play on the word "false," which can be synonymous with "dishonest" in the sense of a fake or artificial appearance or in the sense of a treacherous heart: 

Macbeth: Away, and mock the time with fairest show.
False face must hide what the false heart doth
    know.

In Act 2, Scene 3, following the discovery of Duncan's murder, Malcolm correctly observes that one or more of the thanes may be faking his grief:

Malcolm: To show an unfelt sorrow is an office
Which the false man does easy

In response, Donalbain expresses concern that he and his brother are no longer safe in Scotland, noting that the pretense of loyalty can hide treacherous intentions:

Donalbain: Where we are,
There’s daggers in men’s smiles.

Later on in the play, Macbeth and Lady Macbeth struggle to conceal their guilt and paranoia. In Act 3, Scene 2, they encourage each other to put on a show for the visiting thanes:

Lady Macbeth: Sleek o’er your rugged looks. Be bright and jovial
Among your guests tonight.

Macbeth: So shall I, love,
And so I pray be you. Let your remembrance
Apply to Banquo; present him eminence
Both with eye and tongue: unsafe the while that we
Must lave our honors in these flattering streams
And make our faces vizards to our hearts,
Disguising what they are.

By the end of the play, all these false appearances have fallen apart. Just as the Thane of Cawdor's treachery eventually came to light, Macbeth and Lady Macbeth's crimes are revealed, and they are punished for their duplicity.

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Act 2, scene 2
Explanation and Analysis—Water:

Water is mentioned frequently in Macbeth, often in relation to blood, and it's used as a motif that represents the permanence of guilt.

In Act 2, Scene 2, Macbeth ponders whether an entire ocean would be capable of washing Duncan's blood off his hands: 

Macbeth: Will all great Neptune's ocean wash the blood
Clean from my hand? No, this my hand will rather
The multitudinous seas incarnadine,
Making the green one red.

His belief that the blood on his hands could turn an entire ocean red emphasizes the immensity of the guilt he feels. What's more, references to hand-washing are possibly an allusion to Pontius Pilate, who washed his hands before ordering the crucifixion of Jesus. But while Pilate believed Jesus to be innocent and executed him due to public pressure, Macbeth and Lady Macbeth are in full command of their actions, which they know are morally wrong. And while Pilate's hand-washing was symbolic, Macbeth and Lady Macbeth must physically scrub the blood from their hands. Lady Macbeth is initially confident that Duncan's blood, and therefore her guilt, can be easily washed away:

Lady Macbeth: A little water clears us of this deed.

This confidence proves to be ironic, since, in Act 5, Scene 1, she cannot erase the hallucinatory blood from her hands no matter how obsessively she washes them:

Lady Macbeth: What, will these hands ne'er be clean?

Although water is capable of washing away blood, then, it cannot do the same for guilt.

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Act 2, scene 3
Explanation and Analysis—Duncan's Murder:

The discovery of Duncan's murder in Act 2, Scene 3 is an extended moment of dramatic irony. The audience is aware that Duncan is dead, but Macduff and Lennox are oblivious, an ignorance that Macbeth maintains by making comments that imply the king is still alive.

Lennox: Goes the king hence today?

Macbeth: He does. He did appoint so.

The audience knows that Macbeth is responsible for the murder, but when Macduff announces that Duncan is dead, Macbeth feigns surprise:

Macbeth and Lennox: What's the matter?

Macduff: Confusion now hath made his masterpiece.
Most sacrilegious murder hath broke ope
The Lord’s anointed temple and stole thence
The life o’ th’ building.

Macbeth: What is 't you say? The life?

When Lady Macbeth arrives on the scene, Macduff initially refuses to tell her what has happened, fearing that the news will devastate her feminine sensibilities:

Macduff: O gentle lady,
’Tis not for you to hear what I can speak.
The repetition in a woman’s ear
Would murder as it fell.

This concern is highly ironic, since Lady Macbeth was the one who planned and assisted with the killing of Duncan. In Act 1, Scene 7, she even questioned her husband's manhood when he proved reluctant to carry out the crime:

Lady Macbeth: Who dares receive it other,
As we shall make our griefs and clamor roar
Upon his death?

In the same scene, Macbeth and Lady Macbeth plan how they will pretend to react to news of Duncan's death with grief and horror:

Lady Macbeth: Who dares receive it other,
As we shall make our griefs and clamor roar
Upon his death?

As a result, in Act 2, Scene 3, the audience sees through Lady Macbeth's swooning and Macbeth's explanation for killing Duncan's guards:

Macbeth: O, yet I do repent me of my fury,
That I did kill them.

Macduff: Wherefore did you so?

Macbeth: Who can be wise, amazed, temp’rate, and furious,
Loyal, and neutral, in a moment? No man.
Th’ expedition of my violent love
Outrun the pauser, reason. [...]

In this passage, Macbeth tries to suggest that he flew into a "violent" passion that overtook his ability to see "reason." So although the other thanes believe him when he claims to have murdered the guards out of a sense of rage and loyalty, the audience knows that he did it to conceal evidence of his own crime—creating yet another instance of dramatic irony.

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Explanation and Analysis—False Appearances:

When the Weird Sisters speak their famous line—"Fair is foul and foul is fair"—in Act 1, Scene 1, they introduce the idea that not everything in Scotland is as it seems. This motif of false and deceptive appearances persists throughout Macbeth, and the tension between how things appear and how they really are means that the play is often deeply ironic.

In Act 2, Scene 4, Duncan laments the fact that one cannot divine a person's intentions just by looking at them:

Duncan: There’s no art
To find the mind’s construction in the face.

The Thane of Cawdor appeared to be an honorable and loyal thane, but this appearance disguised a traitorous nature.

In Act 1, Scene 5, Lady Macbeth chastises Macbeth for his expression, which betrays his thoughts, and counsels him to play the part of the gracious host:

Lady Macbeth: Your face, my thane, is as a book where men
May read strange matters. To beguile the time,
Look like the time. Bear welcome in your eye,
Your hand, your tongue. Look like th’ innocent
    flower,
But be the serpent under ’t.

Just as the "pleasant seat" of Inverness conceals the devious machinations of its mistress, Macbeth's welcoming behavior disguises his murderous intentions.

In Act 1, Scene 7, Lady Macbeth further instructs her husband to make a spectacle of his grief following Duncan's murder so that no one will suspect that he is responsible:

Lady Macbeth: Who dares receive it other,
As we shall make our griefs and clamor roar
Upon his death?

Macbeth responds with a play on the word "false," which can be synonymous with "dishonest" in the sense of a fake or artificial appearance or in the sense of a treacherous heart: 

Macbeth: Away, and mock the time with fairest show.
False face must hide what the false heart doth
    know.

In Act 2, Scene 3, following the discovery of Duncan's murder, Malcolm correctly observes that one or more of the thanes may be faking his grief:

Malcolm: To show an unfelt sorrow is an office
Which the false man does easy

In response, Donalbain expresses concern that he and his brother are no longer safe in Scotland, noting that the pretense of loyalty can hide treacherous intentions:

Donalbain: Where we are,
There’s daggers in men’s smiles.

Later on in the play, Macbeth and Lady Macbeth struggle to conceal their guilt and paranoia. In Act 3, Scene 2, they encourage each other to put on a show for the visiting thanes:

Lady Macbeth: Sleek o’er your rugged looks. Be bright and jovial
Among your guests tonight.

Macbeth: So shall I, love,
And so I pray be you. Let your remembrance
Apply to Banquo; present him eminence
Both with eye and tongue: unsafe the while that we
Must lave our honors in these flattering streams
And make our faces vizards to our hearts,
Disguising what they are.

By the end of the play, all these false appearances have fallen apart. Just as the Thane of Cawdor's treachery eventually came to light, Macbeth and Lady Macbeth's crimes are revealed, and they are punished for their duplicity.

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Act 3, scene 2
Explanation and Analysis—Death and Peace:

In Act 3, Scene 2, Macbeth makes an ironic statement about death and peace:

Better be with the dead,
Whom we, to gain our peace, have sent to peace,
Than on the torture of the mind to lie
In restless ecstasy. Duncan is in his grave.
After life’s fitful fever he sleeps well.
Treason has done his worst; nor steel nor poison,
Malice domestic, foreign levy, nothing
Can touch him further.

This passage frames Macbeth as the real victim of Duncan's murder—the act has brought Macbeth nothing but trouble, while it seems, ironically, to have benefited Duncan. Now that Duncan is dead, Macbeth argues, he is safe from all kinds of harm, while the living Macbeth still grapples with physical threats and emotional disturbances.

Despite his lofty ambitions, it seems as though Macbeth failed to consider how much responsibility and hard work would be required of him as king of Scotland. In Act 3, Scene 2, Lady Macbeth expresses her belief that she and her husband have actually lost more than they have gained:

Lady Macbeth: Naught’s had, all’s spent,
Where our desire is got without content.

Macbeth already had all the advantages that kingship should afford (admiration, land, wealth) before he was king. Ironically enough, then, his ambition and greed have ultimately made it impossible for him to actually enjoy the very things he already had when he was a thane.

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Explanation and Analysis—False Appearances:

When the Weird Sisters speak their famous line—"Fair is foul and foul is fair"—in Act 1, Scene 1, they introduce the idea that not everything in Scotland is as it seems. This motif of false and deceptive appearances persists throughout Macbeth, and the tension between how things appear and how they really are means that the play is often deeply ironic.

In Act 2, Scene 4, Duncan laments the fact that one cannot divine a person's intentions just by looking at them:

Duncan: There’s no art
To find the mind’s construction in the face.

The Thane of Cawdor appeared to be an honorable and loyal thane, but this appearance disguised a traitorous nature.

In Act 1, Scene 5, Lady Macbeth chastises Macbeth for his expression, which betrays his thoughts, and counsels him to play the part of the gracious host:

Lady Macbeth: Your face, my thane, is as a book where men
May read strange matters. To beguile the time,
Look like the time. Bear welcome in your eye,
Your hand, your tongue. Look like th’ innocent
    flower,
But be the serpent under ’t.

Just as the "pleasant seat" of Inverness conceals the devious machinations of its mistress, Macbeth's welcoming behavior disguises his murderous intentions.

In Act 1, Scene 7, Lady Macbeth further instructs her husband to make a spectacle of his grief following Duncan's murder so that no one will suspect that he is responsible:

Lady Macbeth: Who dares receive it other,
As we shall make our griefs and clamor roar
Upon his death?

Macbeth responds with a play on the word "false," which can be synonymous with "dishonest" in the sense of a fake or artificial appearance or in the sense of a treacherous heart: 

Macbeth: Away, and mock the time with fairest show.
False face must hide what the false heart doth
    know.

In Act 2, Scene 3, following the discovery of Duncan's murder, Malcolm correctly observes that one or more of the thanes may be faking his grief:

Malcolm: To show an unfelt sorrow is an office
Which the false man does easy

In response, Donalbain expresses concern that he and his brother are no longer safe in Scotland, noting that the pretense of loyalty can hide treacherous intentions:

Donalbain: Where we are,
There’s daggers in men’s smiles.

Later on in the play, Macbeth and Lady Macbeth struggle to conceal their guilt and paranoia. In Act 3, Scene 2, they encourage each other to put on a show for the visiting thanes:

Lady Macbeth: Sleek o’er your rugged looks. Be bright and jovial
Among your guests tonight.

Macbeth: So shall I, love,
And so I pray be you. Let your remembrance
Apply to Banquo; present him eminence
Both with eye and tongue: unsafe the while that we
Must lave our honors in these flattering streams
And make our faces vizards to our hearts,
Disguising what they are.

By the end of the play, all these false appearances have fallen apart. Just as the Thane of Cawdor's treachery eventually came to light, Macbeth and Lady Macbeth's crimes are revealed, and they are punished for their duplicity.

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Act 3, scene 4
Explanation and Analysis—Banquo's Ghost:

In Act 3, Scene 4, Macbeth and Lady Macbeth host a banquet for their various lords. As the guests are arriving, Macbeth learns that his plot to murder Banquo has been successful. The resulting scene is therefore filled with dramatic irony—since none of the thanes are aware that Banquo is dead, they speak about him as if he were still alive and fail to find it strange when Macbeth continues to remark on his absence: 

Macbeth: Here had we now our country’s honor roofed,
Were the graced person of our Banquo present,
Who may I rather challenge for unkindness
Than pity for mischance.

Ross: His absence, sir,
Lays blame upon his promise. Please ’t your
    Highness
To grace us with your royal company?

The above exchange is especially ironic because Macbeth, who ordered Banquo's murder, falsely expresses his hope that no tragic accident has befallen him. Ross, oblivious to Banquo's fate, reassures Macbeth that he is merely being rude.

The appearance of Banquo's ghost in Macbeth's seat is another instance of dramatic irony, since only Macbeth and the audience are able to see the specter. The lords, meanwhile, continue to insist that the seat is empty.

Macbeth: The table's full.

Lennox: Here is a place reserved, sir.

Macbeth: Where?

Lennox: Here, my good lord. What is 't moves your highness?

Macbeth: Which of you have done this?

Lords: What, my good lord?

Lady Macbeth, who is also unable to see the ghost, scolds her husband for what she views as irrational and foolish behavior:

Lady Macbeth: This is the very painting of your fear.
This is the air-drawn dagger which you said
Led you to Duncan. O, these flaws and starts,
Impostors to true fear, would well become
A woman’s story at a winter’s fire,
Authorized by her grandam. Shame itself!
Why do you make such faces? When all’s done,
You look but on a stool.

Lady Macbeth thinks that the ghost, like the bloody dagger Macbeth saw earlier, is merely an illusion, but the audience knows that the two visions are different—they never saw the dagger, but they do see Banquo's ghost.

The thanes accept the explanation that Macbeth's behavior is due to his "strange infirmity," and the banquet continues. Macbeth, however, continues to make unprompted comments about Banquo:

Macbeth: I drink to th’ general joy o’ th’ whole table
And to our dear friend Banquo, whom we miss.
Would he were here!

In this passage, Macbeth is expressing his regret at having killed Banquo, since he now finds himself haunted by the man's ghost. But the thanes, who are ignorant of Banquo's death and Macbeth's involvement, think that Macbeth is merely disappointed about Banquo's absence.

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Explanation and Analysis—Macbeth's Confidence:

In Act 4, Scene 1, the Weird Sisters reveal several prophecies to Macbeth. Most notably, one of their summoned apparitions declares that "Macbeth shall never vanquished be until / Great Birnam Wood to high Dunsinane Hill / Shall come against him." Macbeth, believing such a thing to be impossible, interprets the prophecy as an assurance that he will never be defeated:

That will never be.
Who can impress the forest, bid the tree
Unfix his earthbound root?

Macbeth's confidence in the integrity of the natural world is ironic, since the laws of nature have already been abandoned in the wake of Duncan's murder. In Act 2, Scene 4, the audience learns that animals have begun to behave in ways that are contrary to their natural instincts: an owl, a bird naturally inclined to hunt mice and other vermin, has killed a falcon, and Duncan's tame horses have gone wild and engaged in cannibalism. Macbeth's expectation that nature is predictable is thus mistaken. 

Macbeth also experiences a great disturbance in the natural order when the ghost of Banquo appears in Act 3, Scene 4. After witnessing the specter, Macbeth expresses his belief that the supposedly constant laws of nature have ceased to apply:

The time has been
That, when the brains were out, the man would die,
And there an end. But now they rise again
With twenty mortal murders on their crowns
And push us from our stools.

Macbeth fully accepts that the spirits of the dead can return to torment the living, so it is ironic that he cannot imagine a scenario in which Birnam Wood uproots itself and walks to Dunsinane.  And although he has witnessed the Weird Sisters predict the future and summon powerful supernatural entities (deeds that should be impossible), he still regards the laws of nature as unbreakable and has faith that these laws will protect him.

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Act 4, scene 1
Explanation and Analysis—Macbeth's Confidence:

In Act 4, Scene 1, the Weird Sisters reveal several prophecies to Macbeth. Most notably, one of their summoned apparitions declares that "Macbeth shall never vanquished be until / Great Birnam Wood to high Dunsinane Hill / Shall come against him." Macbeth, believing such a thing to be impossible, interprets the prophecy as an assurance that he will never be defeated:

That will never be.
Who can impress the forest, bid the tree
Unfix his earthbound root?

Macbeth's confidence in the integrity of the natural world is ironic, since the laws of nature have already been abandoned in the wake of Duncan's murder. In Act 2, Scene 4, the audience learns that animals have begun to behave in ways that are contrary to their natural instincts: an owl, a bird naturally inclined to hunt mice and other vermin, has killed a falcon, and Duncan's tame horses have gone wild and engaged in cannibalism. Macbeth's expectation that nature is predictable is thus mistaken. 

Macbeth also experiences a great disturbance in the natural order when the ghost of Banquo appears in Act 3, Scene 4. After witnessing the specter, Macbeth expresses his belief that the supposedly constant laws of nature have ceased to apply:

The time has been
That, when the brains were out, the man would die,
And there an end. But now they rise again
With twenty mortal murders on their crowns
And push us from our stools.

Macbeth fully accepts that the spirits of the dead can return to torment the living, so it is ironic that he cannot imagine a scenario in which Birnam Wood uproots itself and walks to Dunsinane.  And although he has witnessed the Weird Sisters predict the future and summon powerful supernatural entities (deeds that should be impossible), he still regards the laws of nature as unbreakable and has faith that these laws will protect him.

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Act 4, scene 3
Explanation and Analysis—Macduff's Family:

In Act 4, Scene 2 of Macbeth, assassins surprise Macduff's castle at Fife and slaughter his wife and children. Although the arrival of the murderers comes as a horrific surprise to Lady Macduff, the audience has just overheard Macbeth's plan to invade Fife and already knows the fate that will befall Macduff's family. 

The murder of a defenseless woman and her child is an inherently tragic affair, but Shakespeare's use of dramatic irony makes this scene particularly heartbreaking. Lady Macduff quickly establishes herself as a pragmatic and headstrong individual, traits that associate her with comedic heroines like Much Ado About Nothing's Beatrice or The Merchant of Venice's Portia. But Macbeth is not a comedy, and even as the audience gets to know Lady Macduff and listens to the affectionate and rather funny conversation she has with her son, they are keenly aware that she is about to die.

This dramatic irony carries over into Act 4, Scene 3, in which Macduff attempts to convince Malcolm to return to Scotland and overthrow Macbeth. Malcolm suspects that Macduff is actually working for Macbeth, since he sees no other explanation for why Macduff would flee to England without bringing his wife and children: 

Malcolm: Why in that rawness left you wife and child,
Those precious motives, those strong knots of love, 
Without leave-taking?

The fact that Macbeth has just had Macduff's family murdered makes this suspicion ironic. While Malcolm views Macduff's abandonment of his wife and children as a possible indication of treachery, the audience knows that Macduff's loyalty to his country has just come at the expense of his family.

When Ross arrives, the audience immediately knows what he has come to announce. When Macduff discovered Duncan's murder earlier in the play, he responded with intense grief and horror, and the audience expects a similar reaction from him now. But Ross balks at the prospect of revealing what has happened:

Macduff: How does my wife?

Ross: Why, well.

Macduff: And all my children?

Ross: Well too.

Macduff: The tyrant has not battered at their peace?

Ross: No, they were well at peace when I did leave 'em.

The audience understands that, when Ross says that Macduff's wife and children are "well at peace," he means that they are dead, but this double meaning is lost on Macduff. Ross continues to drag out the dramatic irony, despite Macduff's request that he speak plainly:

Ross: I have words
That would be howled out in the desert air,
Where hearing should not latch them.

Macduff: What concern
    they—
The general cause, or is it a fee-grief
Due to some single breast?

Ross: No mind that's honest
But in it shares some woe, though the main part
Pertains to you alone.

Macduff: If it be mine,
Keep it from me. Quickly let me have it.

Ross: Let not your ears despise my tongue forever,
Which shall possess them with the heaviest sound
That ever yet they heard.

Macduff: Hum! I guess at it.

The dramatic irony is heightened because, since Macduff has taken Ross's earlier comment about his wife and children being "well at peace" to mean that they are alive and well, the news of their murder comes as a complete shock. Although it seems as though Ross is attempting to break the news to Macduff as gently as possible, his reluctance to speak plainly makes his final revelation all the more devastating.

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Act 5, scene 1
Explanation and Analysis—Delicate Air:

In Act 1, Scene 6, Shakespeare employs olfactory imagery to describe Macbeth's castle at Inverness. Duncan and Banquo, oblivious to the fact that the castle will soon become the site of a violent murder, comment on the excellent quality of the air:

Duncan: This castle hath a pleasant seat. The air
Nimbly and sweetly recommends itself
Unto our gentle senses.

Banquo: This guest of summer,
The temple-haunting martlet, does approve,
By his loved mansionry, that the heaven’s breath
Smells wooingly here. No jutty, frieze,
Buttress, nor coign of vantage, but this bird
Hath made his pendant bed and procreant cradle.
Where they most breed and haunt, I have
    observed,
The air is delicate.

This passage is highly ironic, since the pleasant odor that Duncan and Banquo spend so much time discussing is later replaced by the stench of blood. In what may be a subtle instance of foreshadowing, their commentary contrasts sharply with Lady Macbeth's line in Act 5, Scene 1:

Lady Macbeth: Here’s the smell of the blood still. All
the perfumes of Arabia will not sweeten this little
hand.

It is also ironic that so many martlets have decided to build their nests in the walls of Macbeth's castle. Martlets, also called martins, are small birds in the swallow family that often roost in the walls of tall buildings or, as Banquo mentions, in church steeples. The presence of these church-dwelling birds, along with Banquo's use of the phrase "heaven's breath" gives the atmosphere of Inverness a holy quality. This sacred appearance is especially ironic given the fact that, in the previous scene, Lady Macbeth encouraged her husband to "Look like the innocent flower, / But be the serpent under it"—that is, to behave like the treacherous snake in the Garden of Eden.

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Explanation and Analysis—Water:

Water is mentioned frequently in Macbeth, often in relation to blood, and it's used as a motif that represents the permanence of guilt.

In Act 2, Scene 2, Macbeth ponders whether an entire ocean would be capable of washing Duncan's blood off his hands: 

Macbeth: Will all great Neptune's ocean wash the blood
Clean from my hand? No, this my hand will rather
The multitudinous seas incarnadine,
Making the green one red.

His belief that the blood on his hands could turn an entire ocean red emphasizes the immensity of the guilt he feels. What's more, references to hand-washing are possibly an allusion to Pontius Pilate, who washed his hands before ordering the crucifixion of Jesus. But while Pilate believed Jesus to be innocent and executed him due to public pressure, Macbeth and Lady Macbeth are in full command of their actions, which they know are morally wrong. And while Pilate's hand-washing was symbolic, Macbeth and Lady Macbeth must physically scrub the blood from their hands. Lady Macbeth is initially confident that Duncan's blood, and therefore her guilt, can be easily washed away:

Lady Macbeth: A little water clears us of this deed.

This confidence proves to be ironic, since, in Act 5, Scene 1, she cannot erase the hallucinatory blood from her hands no matter how obsessively she washes them:

Lady Macbeth: What, will these hands ne'er be clean?

Although water is capable of washing away blood, then, it cannot do the same for guilt.

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Act 5, scene 3
Explanation and Analysis—Death and Peace:

In Act 3, Scene 2, Macbeth makes an ironic statement about death and peace:

Better be with the dead,
Whom we, to gain our peace, have sent to peace,
Than on the torture of the mind to lie
In restless ecstasy. Duncan is in his grave.
After life’s fitful fever he sleeps well.
Treason has done his worst; nor steel nor poison,
Malice domestic, foreign levy, nothing
Can touch him further.

This passage frames Macbeth as the real victim of Duncan's murder—the act has brought Macbeth nothing but trouble, while it seems, ironically, to have benefited Duncan. Now that Duncan is dead, Macbeth argues, he is safe from all kinds of harm, while the living Macbeth still grapples with physical threats and emotional disturbances.

Despite his lofty ambitions, it seems as though Macbeth failed to consider how much responsibility and hard work would be required of him as king of Scotland. In Act 3, Scene 2, Lady Macbeth expresses her belief that she and her husband have actually lost more than they have gained:

Lady Macbeth: Naught’s had, all’s spent,
Where our desire is got without content.

Macbeth already had all the advantages that kingship should afford (admiration, land, wealth) before he was king. Ironically enough, then, his ambition and greed have ultimately made it impossible for him to actually enjoy the very things he already had when he was a thane.

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