In Act I of The Crucible, Reverend Parris assembles the congregation for prayer. At the same time that little Betty is upstairs in bed sick from unknown causes. When the congregation begins to pray they hear screams from above. They believe that she is screaming because she cannot stand to hear prayer.
Betty screams when she hears the Lord's prayer, the Lord's name.
"Meanwhile, as a psalm is sung in the room downstairs, Betty claps her hands over her ears and begins whining loudly. Parris and several others come rushing upstairs to see what has happened. Betty’s behavior is taken as a sign of witchcraft, which has made it impossible for the girl to hear the Lord’s name."
In reaction to the news that the Parris girls are witched, townspeople gather outside the home to pray and sing gospel. At the exact moment that the words "going up to Jesus" are sung, Betty "claps her ears suddenly and whines loudly." She then proceeds to sit up from her "comatose" state and screams. Ironically, her screams are in response to Abigail and Proctor's conversation about their illicit affair, which is taking place before the young girl. However, Mrs. Putnam believes that Betty "cannot bear to hear the Lord's name." This incident fuels the belief that witches and evil are in Salem, thus strengthening the town's hysteria.
The Puritans did believe that someone who has been bewitched would be unable to bear hearing the Lord's name. Therefore, when Betty, prone upon her bed, screams as the village sings a hymn below, almost everyone interprets it as proof that she's been bewitched. However, Betty screams just as the conflict between John Proctor and Abigail Williams comes to a head. Betty knows that Abigail drank a charm to kill Elizabeth Proctor, John's wife, the night before, and she seems to feel very anxious about this fact. When Abigail tries to coax Betty awake, Betty actually confronts her with this secret: it seems like the worst thing they did in the woods, and as much as Abigail wants to hide it from everyone else, Betty seems to be terrified by the fact that she saw her cousin drink blood to murder an innocent woman in their village.
When Abigail yells at John, reminding him of how he disillusioned her about their home, insisting that he still loves her, it all must be too much for little Betty, who lets out a scream and covers her ears. She would not be too young to know that what they did in the forest was wrong and that the girls would be punished terribly were it discovered. Hearing Abigail with John after Abigail tried to kill his wife must be too much for her to bear.