Of further concern to Macbeth is the disparity between his own reputation and the world's perception of Duncan as a good and virtuous king. The final section of the speech contains an apocalyptic vision in which he imagines Duncan's virtue and pity proclaimed as if by angels and cherubim from a storm-filled sky. This doom-laden vision, whose imagery (for example, "trumpet-tongued") reflects that of the biblical Day of Judgment, gives way in turn to a nagging self-doubt. Whereas he pictures the angels and cherubim "horsed upon the sightless couriers of the air," Macbeth admits that he himself has "no spur / to prick the sides of my intent but only / Vaulting ambition which o'erleaps itself / And falls on the other [side]" (25–28).
Lady Macbeth must immediately detect Macbeth's self-doubt. When Macbeth admits to her that his golden reputation might lose its "gloss," she sets out to strengthen his resolve by mocking his perceived weakness. Her questions drive further the wedge between daring and doing, between courage and action, between desire and fulfillment. To these, she adds a distinction between masculinity and femininity: In contrast to her own self-proclaimed manliness, she pours scorn upon her husband's lack of courage. She tells him he is "green," "a coward," and that he resembles the proverbial "poor cat" who wanted the fish but would not get its paws wet. Finally, and most damningly, she tells him that her own lack of pity would extend to murdering her own child as it suckled at her breast. With this one terrifying example, she confirms that "the milk of human kindness" is absent in her.
