The letter of the law concerns adhering to the strict, inflexible moral codes which govern society and help cultivate a civil community. The letter of the law is a significantly narrower, literal interpretation of what the law states.
In contrast, the spirit of the law acknowledges the same moral codes but allows for a more nuanced, flexible interpretation. The spirit of the law embodies what the law is meant to convey.
One of the most prominent examples of the difference between the letter of the law and the spirit of the law takes place following Bob Ewell's death. The letter of the law requires Sheriff Tate to inform the community of Boo's heroics by telling them that Boo killed Bob Ewell in self-defense. However, Sheriff Tate obeys the spirit of the law by telling the community that Bob fell on his own knife, rescuing Boo from the community’s limelight.
In regards to chapter five, one could argue that Jem follows the letter of the law but not the spirit of the law by continuing to play the Boo Radley game at the beginning of the chapter. In chapter four, Atticus instructed the children to stop playing the Boo Radley game because he sympathizes with their reclusive neighbor and understands that the game is embarrassing to Boo. In doing so, Atticus is following the spirit of the law by attempting to prevent Boo from experiencing further embarrassment and ridicule. In order to bypass his father's instructions, Jem follows the letter of the law, according to Atticus's rules, by simply changing the names of the characters and continuing to play a different version of the same game. Scout says,
He still maintained, however, that Atticus hadn’t said we couldn’t, therefore we could; and if Atticus ever said we couldn’t, Jem had thought of a way around it: he would simply change the names of the characters and then we couldn’t be accused of playing anything. (22)
Although Jem literally interprets Atticus's words and does not technically play the original Boo Radley game, he does not follow the spirit of the law, which was meant to protect Boo’s reputation. Essentially, Jem changes the names of the characters but continues to play the game, which is rude and inconsiderate.