Stars hide your fires; Let not light see my black and deep desires: The eye wink at the hand: yet let that be. Which the eye fears, when it is done to see.
In Macbeth Act I, Scene four, Macbeth speaks of his "black and deep desires." Only earlier had Macbeth wondered about the witches' prediction that he gain control of the cawdor; he now wonders if their prediction concerning the kingship might also prove true. Macbeth instructs the "stars [to] hide your fires," because he wants his secret yearning for the throne to remain covered in darkness, especially the fact that he would be willing to do anything, including murdering Duncan, the rightful king, to achieve his ambition.
In addition to the stars hiding their light to cover Macbeth's desires in darkness, Macbeth would also have his "eye wink at the hand," meaning that his eyes would be blind to the actions of his hands. Macbeth himself does not want to see what he must do to achieve the throne, but at the same time, he urges "let that be what the eye fears, when it is done, to see." This statement suggests that even though he does not wish to see what must happen, he desires the end result, the throne, all the same.
Ultimately, these four lines of Macbeth's reveals two important considerations of his character:
1) Ambition--He wants the throne very badly, but does not want anyone to know how far he would be willing to go in order to achieve it.
2) Cowardice--He does not want to have to face the reality of the consequences of his action. He fears what he must do, like murdering Duncan, but still wants his death and the throne all the same.