1. The Three Witches:
- The play introduces three witches, often referred to as the "Weird Sisters." Their presence and the repetition of the number three establish a supernatural and ominous tone, creating a sense of mystery and foreboding.
2. The Witches' Prophecies:
- The witches deliver prophecies to Macbeth in sets of three. For example, they hail him as Thane of Cawdor, Thane of Glamis, and "King hereafter," using three distinct titles. This threefold prophecy foreshadows Macbeth's rise to power and the tragic consequences that follow.
3. The "Double, Double, Toil and Trouble" Chant:
- In Act IV, Scene I, the witches engage in a chant that contains the phrase "double, double" repeatedly. This emphasis on doubling suggests duplicity, deception, and the unraveling of Macbeth's mental state.
4. The Apparitions:
- When Macbeth visits the witches again, they conjure three apparitions: an armed head, a bloody child, and a crowned child holding a tree. These apparitions deliver cryptic warnings about Macbeth's future, each representing different aspects of his fate.
5. The Three Murderers:
- In Act III, Scene IV, Macbeth hires three murderers to kill Banquo and Fleance. The presence of three murderers reinforces the idea of fate and the inevitability of Macbeth's downfall.
6. The Final Prophecy:
- In Act IV, Scene I, the witches reveal their final prophecy to Macbeth: "none of woman born / Shall harm Macbeth." This prophecy, while seemingly reassuring, ultimately leads to Macbeth's downfall as he misinterprets it and becomes overconfident.
The repeated use of the number three throughout the play adds to the supernatural atmosphere and contributes to the themes of fate, ambition, and the consequences of one's actions. It serves as a reminder of the underlying forces at play that drive the tragic events of the story.