Witchcraft features prominently in Macbeth. The play opens, in fact, with the weird sisters conjuring on the Scottish heath. The witches are also the figures that set the play in motion when they accurately predict that Macbeth will be crowned king. Clearly, they have supernatural powers but their power over Macbeth is debatable. At times, the weird sisters seem to represent general anxieties about the unknown. They also seem to represent fears of powerful women who invert traditional gender roles. Elsewhere, the witches appear rather harmless, despite their malevolent intentions. Ultimately, the weird sisters are ambiguous figures that raise more questions than can be answered.
Although the weird sisters deliver a prophesy that sets the play into motion, they don't necessarily control Macbeth's actions.
In Macbeth the weird sisters represent the fear of the unknown.