Star Trek: Deep Space Nine, Season 6

Joseph Sisko:
The question is, what are you going to do?

Benjamin Sisko:
The only thing I can do. Stay here and finish the job I started. And if I fail—

Joseph:
“I have fought the good fight. I finished the course. I have kept the faith.”

...

Benjamin:
I have begun to wonder. What if it wasn’t a dream? What if this life we’re leading, all of this—you and me, everything—what if all of this is the illusion?

Joseph:
That’s a scary thought.

Benjamin:
I know. I know. But maybe, just maybe, Benny isn’t the dream. We are. Maybe we’re nothing more than figments of his imagination. For all we know, at this very moment, somewhere far beyond all those distant stars, Benny Russell is dreaming of us.