It is Atticus who describes Tom best during his summation to the jury:
"And so a quiet, respectable, humble Negro who had the unmitigated temerity to 'feel sorry' for a white woman has had to put his word against two white people's." (Chapter 20)
Tom is a hard-working field worker and family man, married with children. Despite his crippled arm, he is a strong man--both morally and physically--capable of earning a meager living in the hot sun and helping others when they are in need. Tom understands his place at the bottom of Maycomb's social ladder, and he politely assists Mayella Ewell whenever she requests it, partly because she is white--no black man should refuse the request of a white person; and partly because he "felt right sorry for her, she seemed to try more'n the rest of 'em--". He has little choice but to have faith in white man's justice once he is accused of raping Mayella, but Atticus must also have explained to him that "The jury couldn't possible be expected to take Tom Robinson's word against the Ewells'." Tom tells the truth on the witness stand, unlike Bob and Mayella, and he answers in a respectful manner: He addresses the prosecutor, Horace Gilmer, as "suh" even after Gilmer repeatedly calls him "boy." Tom understands the position in which he has put himself: To set foot on a white man's property without permission is a risky proposition for a black man, but to enter a white man's house is dangerous. He follows Mayella inside, however, out of a sense of pity for and loyalty to the woman he has helped before, not realizing the ulterior motives she has for him. In the end, Tom gives up on white man's justice, disdaining Atticus's belief that they still have a good chance for Tom to be freed on appeal. Instead, Tom decides to run, showing that he is "tired of white men's chances, and preferred to take his own."