In To Kill A Mockingbird, what is a quote that proves that Tom Robinson was not involved in the murder because he is not left handed?
Tom Robinson could not have beaten up Mayella Ewell because he is crippled on his left side.
Early in the trial, Atticus establishes that Mayella was attacked by a left handed person, and that Bob Ewell is indeed left handed.
Atticus was trying to show… that Mr. Ewell could have beaten up Mayella. …If her right eye was blacked and she was beaten mostly on the right side of the face, it would tend to show that a left-handed person did it. (ch 17)
Scout is not impressed. She figures that Tom Robinson could just as easily be left handed, and then there is no reason for all of the fuss. After all, she is a child. She can follow most of the proceedings, but she does not see the bigger picture.
We see that Tom Robinson is crippled when they try to swear him in and he can’t keep his left hand on the Bible.
Thomas Robinson reached around, ran his fingers under his left arm and lifted it. He guided his arm to the Bible and his rubber-like left hand sought contact with the black binding. As he raised his right hand, the useless one slipped off the Bible and hit the clerk's table. (ch 19)
Tom could not possibly have attacked Mayella Ewell. Since Atticus went to so much trouble to demonstrate that she was attacked by a left handed person, it did not take much to get the jury’s attention when they saw that Tom could not use his left hand.
Unfortunately, being physically unable to commit the crime was not enough for the jury. It was still a black man’s word against a white woman’s.
While Mayella is testifying that Tom Robinson assaulted and raped her, Atticus asks Mayella to identify her perpetrator. Scout recalls seeing Tom Robinson stand up for the first time and notices his obvious handicap. Scout says,
"He looked oddly off balance, but it was not from the way he was standing. His left arm was fully twelve inches shorter than his right, and hung dead at his side. It ended in a small shriveled hand, and from as far away as the balcony I could see that it was no use to him." (Lee, 188)
The audience and the community of Maycomb know that Tom Robinson cannot use his left hand at all. The fact that Mayella was beaten predominately on the right side of her face indicates that the perpetrator lead almost exclusively with his left hand. Mayella also had bruises the entire way around her neck, which means that somebody with two good hands must have choked her. All of the circumstantial evidence suggests that Tom Robinson is innocent and that Mayella's father, instead, assaulted his daughter.
During Atticus's closing remarks, he mentions that this case is as simple as black and white and explains Mayella's reasoning for accusing Tom Robinson of rape. Atticus then mentions the evidence which suggests that Bob Ewell assaulted his daughter, given the fact that he is left-handed and Tom Robinson is handicapped. Atticus tells the jury,
"We don’t know, but there is circumstantial evidence to indicate that Mayella Ewell was beaten savagely by someone who led almost exclusively with his left." (208)