Importance of three witches in Macbeth by Shakespeare / Role of the three witches in Macbeth.

               The three witches that are introduced at the very beginning of the play, are responsible for the introduction of the ideas that caused Duncan’s death and Macbeth’s destruction. They hail Macbeth as Thane of Glamis, Thane of Cawdor and King of Scotland. Macbeth is already Thane of Glamis. But when Duncan makes him Thane of Cawdor, he begins to believe the rest of the prophesy of witches will come true that he will be the king.
The witches can predict the future, they can add temptation, and influence Macbeth, but they cannot control his destiny. When he becomes king after murdering Duncan, he chooses to follow up by killing Banquo and Macduff’s family. He is not forced to by the witches. The witches make him believe that he is invincible, so that he fights even when he knows that it will mean his doom. Macbeth's downfall is foreseen planned by the weird sisters, but it was Macbeth's own free will that lead him to it.