The opening dialogue sets the scene: It is past midnight, the moon has set, and the "candles" of heaven — the stars — cannot be seen. Symbolically, the airy lightness that greeted Duncan's arrival at the castle in Act I has completely vanished, to be replaced by brooding darkness.
In this opening scene of Act II, as in the later Porter scene, the audience feels momentarily suspended from the action but in no way removed from the intensity of emotion as the innocent Banquo and his son pass the time of night. The moment at which Banquo so very nearly draws his sword on a potential intruder (actually Macbeth) is a master-stroke of dramatic irony: Banquo has no idea of what the audience knows.
The dagger speech (32–65) is, deservedly, one of the most celebrated in Shakespeare. Like "If it were done" (Act I, Scene 7), this soliloquy is a fascinating piece of stage psychology. The structure of the lines precisely echoes the swings from lucidity to mental disturbance that characterize Macbeth throughout the play. There are three false alarms: "I see thee still . . . I see thee yet . . . I see thee still!" Between each of these alarms comes a moment of respite in which Macbeth appeals to the world of the physical senses: "Art thou not . . . sensible to feeling?" "Mine eyes are made the fools of the other senses," and "It is the bloody business which informs thus to mine eyes."
