In Measure for Measure the whole plot centers around death. Death as penance for something that is wrong, death as feared, death as accepted . . . etc. Everything being said really made me think.
As Isabella states, "The sense of death is most in apprehension, and the poor beetle that we tread upon in corporal sufferance finds a pang as great as when a giant dies." In a kind of gross, but very dramatic way Isabella is talking about how precious life is. The focus is on sin and punishment, the action and then the consequence. However, instead of constructing the play around justice and mercy, Shakespeare explores the idea of true verses false.
The executioner of justice himself becomes polluted by the sin he is trying to get rid of. How does this change the story? There is something that is morally wrong about a person who will execute someone for a sin they themselves will commit.
So then, what are we supposed to learn from it? I think a lot of it is simply human life. Shakespeare is famous for his saying, "Some rise by sin, and some by virtue fall" because it states to eloquently the truth. Life is not 'just.'
"The greatest minds are capable of the greatest vices as well as of the greatest virtues."
- Rene Descartes
It then comes down to what we do with what we have, rather than just what we have. Shakespeare writes about people who have great opportunities given them, like William III, Henry V (Hal), Macbeth, etc. and then about what they do with it. Some people fail, some rise and succeed. Shakespeare also discusses the responsibility those who have power hold.
"Those with great power, have great responsibility."
- Spider Man's Uncle.
Being a hero is less about where we stand in life, than what we do.