Speak, then, to me, who neither beg nor fearYour favors nor your hate.
Act 2, Scene 4
The sovereignty will fall upon MacbethThine own lives' means! Then 'tis most likeThriftless ambition, that will ravin upGainst nature still!
Act 5, Scene 1
Out, damned spot! Out, I say!
Macbeth and Banquo get told by the witches their futures. Macbeth's ambition to be king needs to be achieved by murder. He wants this to happen so badly that he will stop at nothing to get this title even if it means killing Duncan. King Duncan and Malcolm are two threats to his kingship. Once Duncan announced that Malcolm as his successor or heir to the throne, he instantly became another obstacle Macbeth would have to overcome.
King Duncan is killed by Macbeth. Ross is saying in agreement that ambition is what killed Duncan He goes on to blame Duncan's children for his death which is false. Duncan's children would never kill their own father. Really Macbeth is the one he should be pointing the finger at.
Lady Macbeth is being tormented by the fact that she can't wipe her hands ofDuncan's blood. She was the one who manipulated Macbeth into murdering Duncan by questioning his manhood. She felt that Macbeth was too mentally weak for that task. By doing this, Macbeth felt more compelled to go through with the murder. She was the mastermind of it all and had her ambition to be the queen.She ends up killing herself in despair.