In the novel To Kill a Mockingbird, what are some quotes that would explain why Dill and/or Tom Robinson are "mockingbirds"?

Mockingbirds are symbolic of innocent individuals throughout the novel. Similar to mockingbirds, innocent individuals do nothing to harm others; they bring joy to the people they encounter. At the beginning of the novel, Dill is an innocent child who has yet to be exposed to racial discrimination and injustice. He is Jem and Scout's good friend and is always entertaining them in the summertime. Dill's innocence and positive attitude make him a symbolic mockingbird. During the trial of Tom Robinson, Dill gets upset and begins to cry. After Scout walks him out of the courtroom, he tells her that Mr. Gilmer made him sick. He says,

"Well, Mr. Finch didn't act that way to Mayella and old man Ewell when he cross-examined them. The way that man called him 'boy' all the time an' sneered at him, an' looked around at the jury every time he answered---" (Lee 266)

Dill says that Mr. Gilmer had no business treating Tom Robinson with contempt, and he could care less if Tom was black. For Dill, witnessing racial discrimination is traumatic and this is the moment he loses his childhood innocence. His reaction portrays why his character is a symbolic mockingbird.

Similar to Dill, Tom Robinson is considered a mockingbird because he does nothing to harm anybody and brings joy to those around him. While Tom is on the witness stand, Atticus asks him if he was paid for his services to Mayella. Tom says,

"No suh, not after she offered me a nickel the first time. I was glad to do it, Mr. Ewell didn't seem to help her none, and neither did the chillun, and I knowed she didn't have no nickels to spare." (Lee 256)

Tom's helpful and considerate response portrays him as a symbolic mockingbird. Tom never hurt Mayella and was only trying to help her. Tragically, Tom falls victim to racial injustice and is wrongfully accused of raping Mayella Ewell.