The story of Macbeth is a well written work of art. Its' characterization and themes are carried by the images set forth in the book. One important image was the supernatural.
These images were portrayed through the "weird sisters," whose foretelling knowledge contributed to the characterization of the main character, Macbeth.
Macbeth's cruel intentions can be seen through his characterization from his opening. "So foul and fair a day I have not seen," demonstrates Macbeth's dissatisfaction with his current position in society. This a very similar statement made by the three witches in the opening act in which they explained that all good is bad and all bad is good.
The witches set the mood for the theme with their prophecy to Macbeth that he will become king. This prediction fuels Macbeth's urge to become king, but at the same time he still holds on to his morals while his wife proposes a plan to kill Duncan, the king.
Ultimately, Macbeth gives in to the classic tragic hero flaw as he lets his pride take control of his actions. Macbeth's reluctance to kill Duncan is quickly overcome by his ambition to become king and his wife's evil intentions.
His wife's hypnotic ways convince him and his reluctance begins to diminish. The witches call upon three apparitions that represent three new predictions regarding Macbeth's life. These prophecies give Macbeth a false sense of security, and he becomes further engulfed by his desires to survive. This is shown when the second apparition tells Macbeth that "...for none of women born/Shall harm Macbeth." The witches are the final piece of Macbeth's wrath.
Macbeth's sense of pride and lack of morale are fueled by the witches unneeded prophecies. Due to these prophecies, the supernatural played a major role in defining the characterization of Macbeth and the theme of the story.