Final answer:
Macbeth's quote about the stars and his desires signifies his wish to conceal his intention to murder Duncan. It suggests the use of darkness as a metaphor to hide his guilt and highlights the themes of evil, guilt, and appearance versus reality in Shakespeare's play.
Step-by-step explanation:
The idea demonstrated when Macbeth expresses 'Stars, hide your fires; Let not light see my black and deep desires,' is his wish for darkness to conceal his evil thoughts and forthcoming actions. This line from Shakespeare's play reveals Macbeth's acknowledgment of his own malicious intentions in planning to murder King Duncan, and his desire to hide these treacherous thoughts from the heavens, which he associates with the watchful eyes of the gods. The darkness becomes a metaphorical cloak for his guilt and evil deeds.
Additionally, in other parts of the text, Macbeth grapples with the moral and psychological consequences of his plot. He realizes that, like a poison, the violent actions he contemplates may return to harm him (the 'poison'd chalice' to his own lips). His guilt is further highlighted after the murder when he hears voices saying 'Macbeth does murder sleep' and acknowledges that he will never sleep peacefully again, demonstrating his tormented conscience.
Lady Macbeth's role in spurring Macbeth's resolve ( courage to the sticking-place') and their plan to intoxicate the chamberlains to frame them ('make our guilt trip on their own') further sets the stage for the dark deeds that follow and highlights the theme of appearance versus reality as they prepare to 'mock the time with fairest show' while hiding their deadly intentions.