An idea I had while watching Conan the Barbarian recently...
When Vader knocks down Luke during their duel and sticks the lightsaber in his face, Vader could be re-dubbed with JEJ's line:
"That is strength boy! That is power! What is steel compared to the hand that wields it?"Then cut to Vader cutting off Luke's hand. It could also be said, with the line ending just as Vader cuts his hand off.