Aunt Polly begins Sunday with household prayer. Sid memorized his lines of scripture the day before. Tom still needs to learn his. He chooses a portion of the Sermon on the Mount, since its lines are the shortest he can find. Mary helps him, but he's hopeless. Only after she promises a present does he improve, earning himself a "Barlow" knife.
Though the Bible is the source of morality in the town, Tom is more interested in adventure. Because he could use the knife in his imaginative games, it is a reward that gets him to learn scripture. Neither pleasing his family nor entering heaven weigh as heavily on his mind.
Mary helps Tom wash up so he is ready for Sunday school, to his distress. Sid and Mary love Sunday school. Tom hates it.
Tom is uninterested in being clean, presentable, or upstanding, as the adults are. He just wants to be free to do as he wants..
Before entering Sunday school, Tom takes out several of the treasures he got from his friends for letting them whitewash the fence and trades them to his classmates in exchange for tickets that students can only earn by reciting from memory passages of the Bible. Once a student earns enough of the tickets, they can get an honorary Bible. Tom is not accomplished at learning scripture, but he craves glory.
Tom fails to respect the Bible competition as a symbol of piety and good behavior, instead seeing it simply as a means of achieving superiority over his classmates. His thinking does make some sense: why should a material object signify that a student, through memorization, understands the moral depth of the Bible's lessons?
Mr. Walters lectures the children, who don't pay attention, whispering and teasing one another. Lawyer Thatcher arrives along with the dignified Judge Thatcher, his wife, and his daughter – Tom's crush. The children and their instructors are in awe of the judge.
Judge Thatcher is a man of the highest stature in the eyes of St. Petersburg's residents, as a legal authority and wealthy family man. The distinctions between adult and child behavior disappear as everyone in the classroom shows off for him.
To everyone's surprise, Tom produces enough tickets for a Bible. He gets to sit with the Judge, becoming the envy of his peers, who know he conned his way to the prize. Mr. Walters knows Tom has been somehow devious, but rewards Tom without question.
Mr. Walters, like Tom, is willing to take a short cut to earning the favor of Judge Thatcher. Mr. Walters' underhanded behavior reveals to the children that the social hierarchy of the adult world is as prone to manipulation as their own.
Looking on, Amy Lawrence is moved from pride to anger, as she realizes she is no longer the object of Tom's affections.
As Tom breaks Amy's heart, she grows up a little, learning an adult disappointment.
Judge Thatcher congratulates Tom in front of everyone. But when he asks Tom to name Jesus's first disciples, Tom answers: "David and Goliath!"
Tom's error shames both him and Mr. Walters. Tom's fantasy of being the most envied boy in Sunday school is wrecked. Tom's embarrassment is endearingly comic, however, because he's just a boy. Mr. Walter's professional embarrassment is more serious. Though widespread, selfish behavior is not considered an acceptable value amongst adults, while boys recognize it as a fact of life.