The old man takes Luke and the droids back to his home, where he fills Luke in on his heritage, and gives him a little present...

"What is it?"

"Your father's lightsaber. This is the weapon of a Jedi Knight. Not as clumsy or random as a blaster... an elegant weapon for a more civilized age."

Alyx's jaw drops. "Holy shit. That's the sword Dr. Stantz was using! The one he gave me the patents for!"