The quote from Shakespeare's "Macbeth" reflects the internal conflict and dark intentions of the character as he grapples with the act of murder. The line suggests a decisive action that will lead to significant consequences, marking a point of no return for Macbeth. The bell symbolizes the call to action, ushering him towards his fate, which ultimately leads to guilt and despair.

Furthermore, the mention of Duncan, the king, highlights the gravity of the crime Macbeth is about to commit. The reference to the knell implies a funeral bell, indicative of death and foreboding, indicating that Macbeth's actions will either propel him to a tragic downfall or a temporary rise to power. This moment encapsulates the themes of ambition, fate, and moral corruption present throughout the play.