"And often times, to win us to our harm,
The instruments of…in deepest consequence"
Scene 3 Lines 123-125
Banquo warns Macbeth of the effect the witches' prophecy of him progressing to the position of king may have on him as their first their prophecy of him becoming Thane of Cawdor gas come true.
Act two
At this point in the play, Macbeth's character has already gone from being a loyal, brave warrior to a nervous schemer.
"Is this a dagger which…I have thee not, and yet I see thee still"
Scene 1 lines 33-35
Macbeth is experiencing visions which may be a nervous reaction of his conscience showing him what he will be doing by showing him the weapon. Although Macbeth is about to kill Duncan, he's conscience is intact which is why he has been having doubts about killing Duncan. This is an important milestone along the changes Macbeth inhibited throughout the play.
"To know my deed 'twere best no know myself"
Scene 2 line 73
Macbeth is in a state of disgust, he now realises how dirty the "deed" was, he is accepted Duncan's death but he feels guilty, this is perhaps the final point at which Macbeth is in control
Act three
It is in this act that Macbeth reaches his final state of mind, he becomes paranoid, and sloppy in his murders. It is at this point that he has no remorse and shows know signs of having a conscience. He has began to see murder as a rational solutions to his problems, and he has become more like his wife in Act 1.
"Know that it was he, in times past, which held you
So under fortune"
Scene 1 lines 77-78
Rather than simply ordering the murderers to kill Banquo, Macbeth is trying to convince them they will also benefit from it and that it is their duty as it was hi fault they were so poor. Macbeth's present behaviour is in contrast to his behaviour at the end of Act 1, where he was the one being convinced by his wife that he had something to gain from Duncan's death. In a way, Macbeth has become more powerful in this new state as he is able to manipulate those around him into false beliefs. Nevertheless, he has become sloppy, by choosing somebody to kill Banquo he is passing control of the situation to somebody else.
"Which of you have done this?"
Scene 4 line 49
Macbeth is experiencing another vision, possibly a sign of insanity. The vision is a ghost of Banquo sitting in his place at the feast. Macbeth is deteriorating mentally.
Act five
Act 5 depicts the fall of Macbeth and Lady Macbeth, and the extreme changes of their characters.
"This disease is beyond my practice…who have died holily on their beds"
Scene 1 lines 56 -58
The doctor is describing Lady Macbeth's state of mind as a disease, she has become insane because of the evil deeds her and her husband have committed and now she will come to an untimely end.
Hail king for so thou art. Behold where stands
The usurper's cursed head"
Scene 7 lines 83 & 84
Macbeth has now also come to an untimely end, described as an usurper. Macbeth has now gone from being seen as a victor and a loyal subject, to being seen as evil.
Conclusion
I do not believe Macbeth was a tyrant, but that he was weak minded. Having not heard the witch's prophecy of him becoming Thane of Cawdor Macbeth's actions may not have directed him the same way they did when the witch's prophecy came true. Nevertheless, if he were a true hero the witch's prophecies would not have made any influence on his loyalty to Duncan.
