Here's Carl's letter in full to Negan

Negan,
This is Carl. I was helping someone. I got bit.
We didn't even have to be doing what we were doing. I was just helping someone and now I'm gone.

You might be gone. Maybe my dad made your people give you up and he killed you —
but I don't think so. I think you're still around and you're working on a way out.
Maybe you got out. Maybe you think we're a lost cause and you just want to kill all of us.

I think you think you have to be who you are. I just wonder if this is what you wanted.
I wanted to ask you. I wish I could have.

Maybe you'll beat us. And if you do, there'll just be someone else to fight.
The way out is working together. It's forgiveness. It's believing that it doesn't
have to be a fight anymore. Because it doesn't.

I hope my dad offers you peace. I hope you take it. I hope everything can change.
It did for me.

Start over. You still can.

- Carl