In Macbeth, the theme that ambition corrupts is demonstrated through Macbeth’s transformation from a loyal solider to a murderous tyrant.
In the beginning of the play, Shakespeare goes to great lengths to characterize Macbeth is a brave and loyal soldier. As the bloody sergeant sings his praises, King Duncan declares, “O valiant cousin! Worthy gentleman!” (Act 1, Scene 2). Macbeth is described as bravely fighting and killing the traitor Macdonwald.
If Macbeth had not been considered this great guy in the beginning, his fall would not have been so terrible. The fact that Macbeth is for all intents and purposes an honorable man shows that he really went wrong. We feel bad for Duncan for trusting him.
Macbeth’s transition is influenced by his wife and the witches. The witches seem to be manipulating him even as the play starts. The battle has begun, and they are looking forward to meeting up with him. They are ready to cause some trouble, and something about Macbeth makes him a good target.
Lady Macbeth notes that her husband is not without ambition. Yet she does not think he has it in him to act.
Yet do I fear thy nature;
It is too full o’ the milk of human kindness(15)
To catch the nearest way. (Act 1, Scene 5)
Yet Lady Macbeth also only acts once the witches do, showing that no one was interested in pushing Macbeth along until they intervened.
Even Macbeth himself realizes that something inside him is changing. He had no interest in being king until the witches made the prophecy. He assumes he will be named. When he is not, he gets angry.
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.(Act 1, Scene 4)
Between the two of them, they seem ready to push Macbeth on to ambtition. Yet once he reaches the time, he loses his nerve. It takes Lady Macbeth pushing him to get him to actually kill Duncan.
So did his character change? Macbeth was ambitious, but not ready to act. He was pushed into acting. He then became more ambitious. It was not until he acted, killing Duncan, that he changed. From then on he was bloodthirsty, killing anyone he thought stood in his way. His experiences certainly seem to have corrupted him. Once he killed, it was easier to kill. Once he saw himself as king, it was easier to see himself that way and he was willing to do anything to stay there.