Lady Macbeth develops throughout the play
In many ways, Shakespeare’s Lady Macbeth is an ambiguous character. To some, she is the manipulative embodiment of evil. To others, she is a loyal, supportive wife. In any case, her character develops extensively over the course of the play - just like her husband’s.
At first she appears stronger than her husband
From the very first moment we meet her (in Act 1, Scene 5), Lady Macbeth is strong-willed and ambitious for her husband to succeed. She is reading a letter from her husband about the witches’ prophecy, and unlike Macbeth who initially seems doubtful, Lady Macbeth is more than ready to seize power. Knowing her husband well, she realizes that Macbeth is “not without ambition, but without / The illness should attend it.” (1.5.19-20). She believes he is simply not ruthless enough, and to her that is a weakness.
Lady Macbeth does not spend time reflecting like her husband does; instead she acts immediately. In Shakespeare’s day, women were considered weaker than men. However, in her famous “unsex me” soliloquy, Lady Macbeth calls upon evil spirits to remove her feminine qualities:
Unsex me here,
And fill me from the crown to the toe top-full
Of direst cruelty! make thick my blood;
Stop up the access and passage to remorse [...]
Come to my woman’s breasts,
And take my milk for gall. (1.5.45-52)
She asks to be filled w...