What is shakespeare trying to teach us about guilt in Macbeth?

It's been a long time since I read Macbeth. If I remember correctly, Macbeth teaches us that you must do what ever it take to rise to power, and then maintain it. Any guilt he experiences is simply to show us that he is still a lovable guy at heart no matter the evil things he had to do. Shakespeare wants you to know that it is okay to do evil things, as long as you feel guilty about them after.