Why a Sacrifice?

I could have done the deed
Gabrielle, you didn't have to die
I am darkness, you are light
The world would live without me
I've saved lives, but taken more
How could you give yourself for me?
I cannot understand
You are not to blame
hope was lost because I killed it
Hope was born because I did not stop
Why do you hold the burden in your heart?
Why did you take the blame?

Your sacrifice was brave and noble
You are one so pure of heart
But why let pureness die
When it could have been me?
Why a sacrifice?