"Souls are meant to be protected. A soul doesn't mean much without the person itself, though there are some who would view them as sources of power and nothing else. All those souls in Heaven are guarded for a reason."

Those who looked at soul and saw only power were the people that Castiel was trying to stop, even though he'd been the same way at one point. Not that he had ever wanted to make use of human souls during his fight against Raphael. Monster souls were another issue, and he hadn't felt much guilt in using those.

Looking back on it now, even that much was a mistake, but at least he'd learned his lesson. He had no intention of using souls lightly these days. No, he'd much prefer that they stay where they belong, which was in a human's body.

They could discuss this all Adam wanted, but in the end Castiel's view of it wasn't going to change. Adam's soul might be putting him through Hell right now, but that was better than removing it and leaving an empty husk in its place.

He'd seen Sam without a soul, and it hadn't been a pretty picture.