The quote itself foreshadows the apparent sinister and deceitful nature of the play, in that it brings forth the idea that things that seem fair, good and true may well in fact be evil or foul. Likewise, things that appear evil may possess elements of good in them. This quote is a key component of the play, as the play itself centres around the idea of deception and that what appears on the outside is not always a true reflection of what lies beneath.
Macbeth; the brave, honourable, ambitious Thane of Cawdor, is ironically and evidently controlled by his wife Lady Macbeth. The two are arguably the chief instigators of deceit and “deception”. Macbeth is guilty of deceiving his best friend Banquo, his cousin King Duncan, as well as the public.
The witch’s prophecy plays a key part and is of a significant influence to Macbeth. The prophecies themselves are of a deceptive nature, and contain cryptic messages and double meanings, an example of which being that “none of woman born shall harm Macbeth.” Though Macbeth is praised and talked highly of at the beginning of the play, the witch’s prophecies and his hidden ambitions fuel and contribute to his eventual deceitful and deceptive persona.
Lady Macbeth is ultimately a puppet master, and is highly skilled at persuading others to believe in things that are not entirely true. Her manipulation is evident in Act I Scene V, where she persuades Macbeth to
"Look like the innocent flower, but be the serpent under 't." coercing him to, to put it simply, act all buddy-buddy to King Duncan only to stab him square in the back. Lady Macbeth persuades Macbeth that in order to be successful in his ambitions (spurring from the prophecies) he would need to see past his own good nature and accept her cunning