Probably to symbolize Cincinnatus of Ancient Rome (Who rose up to defend Rome from his plow, defeated the enemies of Rome and returned to his plow 15 days later. And who Washington was often compared.) and the saying "Let Us Beat Swords Into Plowshares."
The original Washington monument was a statue of Washington sitting, handing over a sword.
Probably to symbolize Cincinnatus of Ancient Rome (Who rose up to defend Rome from his plow, defeated the enemies of Rome and returned to his plow 15 days later. And who Washington was often compared.) and the saying "Let Us Beat Swords Into Plowshares."
Handing over a sword, or his hand over a sword?
Handing over. https://1.bp.blogspot.com/_lF6nnKMFVM0/TRzv7dBFOAI/AAAAAAAAFuA/jWvy1RYyUTo/s1600/Original%2BWashington%2Bmonument.jpg