The prophecy in the play Macbeth by William Shakespeare gets the plot going immediately as it starts. The first seen in Act 1 is outside in the thunder and lightening with the weird sisters. They foreshadow that something prophetic will happen in the play when all of the witches chant, "fair is foul, and foul is fair, hover through the fog and filthy air." This paradox instantly tells the reader that strange things will happen in this play. The quote does not even need an analysis; the riddle-like tune to it informs the reader that something peculiar will happen.
In the third scene of Act 1, Macbeth and Banquo meet with the witches and they greet him with three titles, Thane of Glamis, Thane of Cawdor, and King. This gets Macbeth thinking which isn't very good for his health or the health of others around him. He already knows that he will be Thane of Glamis because Macbeth's father, Sinel, had recently passed away. Later on Macbeth sees that the Thane of Cawdor was just killed, and he will become the Thane of Cawdor. Now he sees that two thirds of the prophecy is true. He has an aside (Act 1, Scene 3, lines 128-142) to state this and he is questioning it a little but he believes it and thinks its great that he will be king. He and his wife are very greedy and they are overwhelmed by it and they decide to take action. They decide to kill Duncan, the king, for it is the only way for greedy and impatient Macbeth and Lady Macbeth to accelerate their fates. When Duncan was assassinated and Macbeth was named king the first part of the prophecy was fulfilled. .
The next part of the prophecy was somewhat ambiguous. The weird sisters told Macbeth that he should beware Macduff, that he is safe until Birnan Wood comes to Dunsinane, and that no man born of women can harm Macbeth. When Macbeth learns this he feels invincible, and the only person in his way is Macduff. Macbeth had no idea that Macduff was "untimely ripp"d" or born by a caesarean section.