In Macbeth the witches symbolise the supernatural. The weird sisters evoke Macbeth's ambition; they know how Macbeth will react to their prophecies so they toy with him and deceive him by saying one thing but meaning another. The witches have no conscience; they cause mischief on purpose and enjoy it. The witches provide the foundation for Macbeth's downfall by telling him that he shalt be king hereafter. When Macbeth hears the witches' prophecies, horrible imaginings are opened in his mind. Unlike Banquo who dismisses the witches' prophecies, Macbeth contemplates regicide. The witches plant the seed to Macbeth's downfall. He wants the witches to stay, you imperfect speakers. Tell me more. This shows that Macbeth believes in the idea that he can be king, and that he perhaps has thought about regicide before.
Lady Macbeth is also a large contributing factor to the regicide. If Lady Macbeth was not behind Macbeth plotting the death of King Duncan and manipulating Macbeth into doing The deed, none of the deaths would have occurred, therefore there would be no downfall for Macbeth. Macbeth believes that if chance will have me king, why chance may crown me without my stir, whereas after Lady Macbeth reads the letter Macbeth sends to her, without hesitation, she thinks of regicide. Lady Macbeth knows that Macbeth is too full o'th'milk of human kindness and that she will have to persuade him. Despite Macbeth wanting to proceed no further of this business, Lady Macbeth convinces him by questioning his