Dean and Sam in “Unfinished Business”

Dean

I know you heard him.

Sam

Who?

Dean

Alastair. What he said... About how I had promise.

Sam

I heard him.

Dean

You're not curious?

Sam

Dean, I'm damned curious. But you're not talking about Hell, and I'm not pushing.

Dean

It wasn't four months, you know.

Sam

What?

Dean

It was four months up here, but down there... I don't know. Time's different. It was more like 40 years.

Sam

My God.

Dean

They, uh... they sliced and carved and tore me in ways that you... until there was nothing left. And then, suddenly... I would be whole again... like magic... just so they could start in all over. And Alastair... at the end of every day--every one--he would come over. And he would make me an offer. To take me off the rack. If I put souls on. If I started the torture. And every day, I told him to stick it where the sun shines. For 30 years, I told him. But then I couldn't do it anymore, Sammy. I couldn't. And I got off that rack. God help me, I got right off it, and I started ripping them apart. I lost count of how many souls. The... the things that I did to them.

Sam

Dean... Dean, look, you held out for 30 years. That's longer than anyone would have.

Dean

How I feel, this... inside me... I wish I couldn't feel anything, Sammy. I wish I couldn't feel a damned thing.