Shakespeare presents the prophecies in Act 1, Scene 3 as having a major impact on Macbeth's character.
The witches are seen giving Macbeth prophecies. The first prophecy is " Thane of Cawdor" Macbeth doesn't accept this prophecy as he says, "the Thane of Cawdor lives." However Macbeth later finds out that the Thane of Cawdor was a traitor and had been executed. The King gives Macbeth the title of both Thane of Cawdor and Glamis as an offering of his gratitude , for being loyal to him and his service.
The second prophecy given to Macbeth by the witches is , " All hail Macbeth , that shalt be king hereafter." After the witches give Macbeth this prophecy, Macbeth is seen giving a monologue. "If good, why do I yield to that suggestion ,Whose horrid image doth unfix my hair,And make my seated heart knock at my ribs.." From this we can suggest that Macbeth is talking about the King and taking his life to become King instead as the three weird sisters had prophecised.
From these two prophecies we can see that Macbeth has become more selfish and greedy as he will do anything to fulfil the prophecy of him becoming king in the hereafter. Macbeth leaves his loyalty and generous characteristics to chase the prophecy these three witches had left for him, even if it means to commit treason and summon spirits to help him fulfil these wishes.
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