Answer:
In the Explanation
https://www.quora.com/How-does-Shakespeare-present-Lady-Macbeth-as-a-powerful-woman
there are more examples on this site! :)
Explanation:
"Shakespeare isn’t alive and he didn’t leave any records of his intentions, so the following is a guess: we know that he went out of his way to create moral ambiguity in the play, not about whether or not killing Duncan was a bad act but, rather, about who is responsible.
Consider that he could have written the play without the witches. He could have removed Lady Macbeth from it, too. Or he could have made her ignorant about Macbeth’s plans. He could have had her try to talk him out of them. But he did the opposite. He very clearly had the witches trigger Macbeth’s thoughts about murder; he very clearly had Lady Macbeth goad him and seduce him into doing it; and he very clearly allowed us into Macbeth’s own thoughts, in which he makes the decision to do it.
Rather than telling a simply story in which Macbeth is the bad guy, he tells the story of a man who is besieged by forces from without and from within, all prompting him to do a terrible thing. And then, in the second half of the play, he transcends all the external forces and does even worse things on his own.
Having recently directed the play, I believe Shakespeare works hard to help us identify with Macbeth, and one of Lady Macbeth’s functions is to help us do that. If Macbeth had simply been a psychopath (much like Shakespeare’s Richard III), we would have seen him as a monster through and through.
But, instead, Shakespeare first paints Macbeth as a hero. Then he plays on our emotions in a couple of ways. He lets us into Macbeth’s mind and shows us how continually frightened he is. He also shows us all the forces playing on him: the supernatural, a powerful wife, and his own ambitions. Which allows us to wonder what we’d do in his position. I know for a fact that I would never behave like Iago or Richard III, but in Macbeth’s shoes, would I behave as he does? What if I was put under the same pressures? Even if my answer is no, I still have more pause-for-thought than with the more traditional villains.
Once Shakespeare has us hooked with empathy, he gradually has Macbeth go over-the-top, into a nightmare world of paranoia in which he leaves Lady Macbeth behind him, committing horrible acts she would never sanction, eventually losing her altogether. And he even conjures the witches, a sure sign that he’s gone totally over to the dark side. At which point the play switches to England, and we see Macbeth from the point-of-view of the other characters.
So another function of Lady Macbeth is to be a strong force who loses her strength, stranding Macbeth for the rest of the play on his own. Note that the witches don’t return, either."
