the milk of human kindness - lady macbeth

Yet do I fear thy nature;
It is too full o’ the milk of human kindness
To catch the nearest way.

– William Shakespeare

Macbeth, Act 1, Scene 5. Lady Macbeth fears that her husband is too compassionate to be able to murder Duncan to make the Witches’ prophecy that he will be king come true. A metaphor likens human kindness to “milk,” conjuring up a feminine image that is maternal and nurturing. Lady Macbeth’s words are ironic, since it suggests that Lady Macbeth is a lot less full of that milk than her husband. The passage also suggests that Macbeth is not totally evil at this point.