Examples of foreshadowing in Macbeth Act 1, Scene 3.

When Banquo and Macbeth meet with the witches and hear their portents, the audience is being made aware of events to come. This is foreshadowing. Specifically, Macbeth learns that he will be proclaimed Thane of Cawdor and later King. The witches also allude to the fact that although Banquo will not be King.... his heirs will.