Act IV

Scene i

Gathered around a cauldron, the witches open this act with an incantation. Hecate visits briefly to compliment them on their spell. Macbeth enters and the witches let him see apparitions, which answer Macbeth's unspoken questions. The first apparition tells him to beware of Macduff, the second that 'none of woman born' will harm him and the third that he is safe until Birnam wood 'comes to' the hill at Dunsinane.

Macbeth then presses them to answer a query about Banquo's descendants and the witches show a line of eight kings resembling Banquo, the eighth holding a mirror that shows more that follow. The witches vanish.

Lennox arrives, denies seeing any witches and informs Macbeth that Macduff has gone to England. In an aside, Macbeth resolves to attack Macduff's castle and kill his family.

The witches' scene is a popular one that sets the mood for the dark, supernatural apparitions to come. Hecate's cameo seems out of place, which may indicate that it is not an original part of Shakespeare's text and perhaps Middleton's addition.

The first apparition warns Macbeth about Macduff, which is why Macbeth immediately decides to attack Macduff's castle when he learns that Macduff has gone to England. The second and third apparitions speak ambiguously, which gives Macbeth false confidence about his position. Here, Shakespeare establishes the foundations for dramatic irony with the equivocating apparitions, which he will revisit later in the play.

The appearance of Banquo's kingly descendants undermines Macbeth's temporary security. The eight kings represent the Stuart royal lineage, the eighth king being James I. He holds a mirror to imply that the Stuart line will continue for many generations hence.

Scene ii

Lady Macduff, her son and Ross discuss Macduff's sudden departure from Fife. It appears that Macduff has not explained his mission to his wife. They are surprised by murderers, who rampage the castle.

This scene contrasts the wholesome nature of Macduff's family against the brutality of the murderers, whose first victim is Macduff's young son. The murderers represent Macbeth's reign of terror and the lengths he will go to in order to establish his rule.

Scene iii

Malcolm and Macduff meet in England where Macduff outlines Macbeth's ill deeds. Malcolm pretends to question Macduff's loyalty and then becomes self-critical about his vices, hinting that he would be an inadequate ruler. Macduff maintains that a king with such vices would not be fit to rule, which satisfies Malcolm to reveal that he was merely testing Macduff.

A doctor enters and Malcolm asks after the King of England. The doctor replies that the king cannot meet with them because he is treating sick people. Malcolm explains the illness and remedy to Macduff.

Ross joins them and reports the attack on Macduff's castle and that his family have been murdered. Macduff blames himself for putting them in danger and vows revenge on Macbeth.

The beginning of this scene is designed to show Malcolm as the rightful heir to the throne while highlighting Macduff's loyalty to Scotland. The audience inevitably compares Malcolm to Macbeth. The absence of the English king, due to his devotion to his subjects, also contrasts against Macbeth's murderous reign.

The audience learns more about Macduff's noble traits, such as when he blames himself for putting his family in danger and his courage in resolving to face Macbeth.