In act 1:6 and 7, Macbeth is battling with his conscience and is very confused. He does not want to kill his king because he is afraid of what may happen to him as a consequence. "If th" assassination could trammel up the consequence".
At the beginning of 1:7 he talks to himself and considers the points for and against killing the king. Just as he has talked himself out of the murder his wife arrives, possessed by evil spirits "pour thy spirits in mine ear" to bring her husband back to the dark side. "I have no spur to prick the sides of my intent but only vaulting ambition which o"erleaps itself and falls on th" other - Enter Lady Macbeth" Lady Macbeth sways Macbeth's troubled state of mind into comitting the murder by insulting his masculinity and blackmailing him with her love. "What beast was't then that made you break this enterprise to me? When thou durst do then you were a man." By the end of the scene Macbeths state of mind has changed once again and now he is completely confident that the is going to do the murder "I am settled and bend up each corporal agent to this terrible feat" Throughout the scene, Macbeth acts like a victim of his terrible ambition but he is still in control of himself.
However in act 5:3, Macbeth's state of mind has completely changed, he is no longer in control of his ambition "the firstlings of my heart shall be the firstlings of my hand" and he has become more of a tyrant, shouting at his servants. "The devil damn thee black thou cream faced loon!" "Pull't off I say!" His indecisiveness from 1:7 has been replaced with the complete opposite "The mind I sway by and the heart I bear shall never sag with doubt nor shake with fear" During this scene his mood swings between being depressed "I have lived long enough, my way of life is fallen into the sere" and being angry "I"ll fight till from my bones my flesh be hacked.".
Lady Macbeth's state of mind also changes quite ironically, from 1:7 to 5:1.