That’s why all of you are here. Nobody does it alone, Jack. You needed all of them, and they needed you.

From Finale of LOST :-

Jack Shephard: Are you real?
Christian Shephard: I sure hope so. Yeah, I’m real. You’re real. Everything that’s happened to you is real. All those people in the church, they’re all real too.
Jack Shephard: No. They’re all… They’re all dead.
Christian Shephard: Everyone dies sometime, kiddo. Some of them before you, some… long after you.
Jack Shephard: But why are they all here now?
Christian Shephard: Well, there is no “now”, here.
Jack Shephard: Where are we, Dad?
Christian Shephard: This is a place that you… that you all made together so that you could fine one another. The most important part of your life was the time that you spent with these people. That’s why all of you are here. Nobody does it alone, Jack. You needed all of them, and they needed you.
Jack Shephard: For what?
Christian Shephard: To remember. And to… let go.
Jack Shephard: Kate… She said we were leaving.
Christian Shephard: Not leaving. No. Moving on.
Jack Shephard: Where are we going?
Christian Shephard: Let’s go find out.