Why does Macbeth decide to kill Macduff's family? Explain what this shows about Macbeth.

The witches circle a cauldron, mixing in a variety of grotesque ingredients while chanting "double, double toil and trouble; / Fire burn, and cauldron bubble" (10-11). Hecate appears, they sing all together, and Hecate leaves. Macbeth then enters, demanding answers to his pressing questions about the future. The witches complete their magic spell and summon forth a series of apparitions. The first is an armed head that warns Macbeth to beware the Thane of Fife (Macduff). Macbeth's superstition and belief in the witches' prophecy lead him to eliminate Macduff's family. This also illustrates his ruthlessness.