Macbeth starts out as a weaker character, because he does not stand up for himself when his wife, Lady Macbeth, insults him. He has a bigger conscience than Lady Macbeth, and throughout the play Macbeth feels guilty about killing Duncan. However he desperately wants to be king and will do anything to get that title. Macbeth does believe in morality, and in the beginning of the play he has better morals, than towards the end. Also, he becomes very paranoid after he has Banquo killed.
Macbeth is insulted by Lady Macbeth, especially in the first part of the play which makes him look weaker. For example, when Macbeth decides he does not want to go through with the killing of Duncan, she says to him, "Which thou esteem'st the ornament of life, and live a coward in thine own esteem, letting "I dare not" wait upon "I would," like the poor cat I" the adage?" (I, vii). Macbeth does not want to be a coward, both as a soldier and as a husband, so he accepts the idea to murder Duncan. However, after he kills Duncan he has a big fear of being caught, and he covers it up with his rage. Macbeth shows his rage by killing the guards.
Macbeth has Banquo killed because he is worried that Banquo suspects that he is responsible for the murder of Duncan. This causes Macbeth to go mad and becomes paranoid, because when they go to dinner he sees the ghost of Banquo sitting in his chair. Everyone who was at the dinner was shocked to see Macbeth yelling at an empty chair. He screams, "quit my sight! Let the earth hide thee! Thy bones are marrowless, thy blood is cold; thou hast no speculation in those eyes which thou dost glare with," (III, iv). Macbeth's words and actions cause Lady Macbeth to tell the crowd he is not well sometimes, and since his youth he temporarily has these hallucinations. Macbeth is very scared and he thinks the ghost is real.
Throughout the play, Macbeth's state of mind changes.