Great question. In Of Mice and Men, hands are powerful.
First, when Steinbeck describes George, he says that that he is a defined man. By this he means that George is a decisive man, unlike his friend, Lennie. Here is what Steinbeck says:
Every part of him was defined: small, strong hands, slender arms, a thin and bony nose.
Many body parts of mentioned, but there is a emphasis on hands. His hands were strong. Steinbeck suggests that George was a leader.
More interestingly, when Slim is portrayed, his hands are portrayed as well. The description of Slim in the novel is almost divine. It is no wonder that Slim has the respect of the other men. It is interesting that Steinbeck also focuses on his hands:
His hands, large and lean, were as delicate in their action as those of a temple dancer.
Third, Lennie's hands are also mentioned. They are the most powerful, but whenever he uses them, he uses them wrongly. For instance, he accidentally kill mice and dogs. Later he cripples a man - Curley, and finally he will accidentally kill a woman. Here is how Steinbeck describes the fight scene between Lennie and Curley:
Steinbeck - Of Mice and Men
Curley’s fist was swinging when Lennie reached for it. The next minute Curley was flopping like a fish on a line, and his closed fist was lost in Lennie’s big hand. George ran down the room. “Leggo of him, Lennie. Let go.”
If we put all of this together, hands are powerful, but when they are used wrongly, they can also cause great harm.