Draw a connection between the appearances of the apparitions and the message they have for Macbeth.

As the act opens, the witches carry on the theme of doubling and equivocation that threads throughout the play. As they throw ingredients into their cauldron, they chant "double, double, toil and trouble"—a reminder that their speech is full of double meanings, paradox, and equivocation (IV i 10). The apparitions that the witches summon give equivocal messages to Macbeth, and they appear to know quite consciously that he will only understand one half of their words. Although Macbeth himself has previously acknowledged that "stones have been known to move and trees to speak" (III iv 122), the apparitions give Macbeth a false sense of security. He takes the apparitions' words at face value, forgetting to examine how their predictions could potentially come true.

The theme of doubling is amplified when the witches summon the "show of kings." Each king who appears looks "too like the spirit of Banquo," frightens Macbeth with their resemblance (IV i 128). For Macbeth, it is as if the ghosts of Banquo have returned to haunt him several times over. In the procession of kings, Macbeth also notes that some carry "twofold balls and treble scepters"—as if even the signs of their power have been doubled.