Jack Kline: I can't... think about losing him or... or Sam or you. I-I just... I hate... I hate thinking about it.

Castiel: Yeah. So do I. But, Jack... you know, Sam and Dean, they're human, and they're very extraordinary, brave, special humans, but they're... They're still humans. And humans burn bright, but for a very brief time compared to, you know, things like us. And eventually, they're gone, even the very best ones, and we have to carry on. It's just... It's part of growing up.

Jack Kline: Losing people?

Castiel: Yes.

Jack Kline: What's the point?

Castiel: The point?

Jack Kline: What's the point of being a cosmic being if everyone I care about is just gonna... leave?

Castiel: The point is that they were here at all and you got to know them, you... When they're gone, it will hurt, but that hurt will remind you of how much you loved them.

Jack Kline: That sounds... awful.

Castiel: It is. But it's also living. So when Dean wakes up... And he will wake up... We just have to remember to appreciate the time that we all have together now.