Lady Macbeth wants to rid of her female tenderness and replace it with pure evil. As Macbeth enters Lady Macbeth reveals she is worried that he will give the plot away with his face so she tells him to "look like the innocent flower but be the serpent under"t"(I.V 62-63 ). She has now assumed the role of leadership in their relationship which shows that she is in great control at the beginning of the play.
Lady Macbeth consistently has to reinforce Macbeth's determination to carry out the murder as he wanders around the castle in doubt (I. VII). As Macbeth tries to explain to his wife why it would not be a good idea to carry out the murder and that he will not do it, she turns on him and starts to insult him saying he is a coward "And live a coward in thine own esteem" (I.VII 43 ). This insult is not true because he is a brave solider. She uses it only to try to get him to defend himself and thus carrying out the murder. When he still refuses to murder she goes to the extreme and uses imagery saying that she would rather dash out the brains of a baby than let a chance like this pass them by. "In offering to dash out the brains of "the babe that milks me" (I. vii 55) in effect she ritually murders the naked babe of pity that Macbeth has just summoned" (Shakespeare For Students 265). Her character appears to be getting more fiendish and wicked by the minute. Lady Macbeth finally convinces him to commit the crime and tells him of the evil plan she has devised: make the guards drunk then murder Duncan and the guards shall get the blame. "In this great central scene, Lady Macbeth makes the murder of Duncan the test of Macbeth's virility; if he cannot perform the murder, he is in effect reduced to the helplessness of an infant subject to her rage. As she progresses from questioning Macbeth's masculinity to imagining herself dashing out the brains of her infant son, she articulates a fantasy in which to be less than a man is to become interchangeably a woman or a baby, terribly subject to the wife/mother's destructive rage" (Shakespeare For Students 287).
