[Luke has seen a vision of Han, Leia and Chewie being tortured in Cloud City]
Luke: I saw a city in the clouds. They were in pain.
Yoda: It is the future you see.
Luke: Will they die?
Yoda: Difficult to see. Always in motion is future.
Luke: I've gotta go to them.
Yoda: Decide you must what to serve them best. If you leave now, help them you could but you would destroy all for which they have fought and suffered.