Jem tells Scout that when he went to get his pants they were folded and someone tried to mend them for him.
The incident with Jem’s pants is one of the most important ones in the book. Scout, Jem, and Dill are investigating the Radley house yet again, even though Atticus told them he’d wear them out if they bothered the Radleys anymore. Jem’s pants got caught and he ran as Nathan Radley shot at them, thinking he was an intruder.
They told Atticus and Rachel that they were playing strip poker with matches, and Atticus told Jem to get his pants. He couldn’t, because they were on the Radley porch. Jem got ready to go back and get them. Even Nathan would never shoot a little boy, but Scout did not know that. She begged him not to go.
I was desperate: "Look, it ain't worth it, Jem. A lickin' hurts but it doesn't last. You'll get your head shot off, Jem. Please..." (ch 6)
Jem goes anyway, telling her he can’t bear to have Atticus disappointed in him. Later, he tells her what happened. He went back and found them folded on the fence. They had been inexpertly mended. The incident frightens Jem.
Jem shuddered. "Like somebody was readin' my mind... like somebody could tell what I was gonna do. Can't anybody tell what I'm gonna do lest they know me, can they, Scout?" (ch 7)
This incident demonstrates Jem’s strength of character and bravery, but it also shows Boo’s. Boo risked a lot to help Jem, because we saw how Nathan Radley reacted when Boo was leaving presents for the Finch kids in the tree.
Jem is fully aware that Boo will face consequences for helping the Finch kids, and later begs Atticus not to tell anyone that Boo put a blanket on Scout’s shoulders at the fire. He appreciates Boo's gestures of friendship, and understands them for what they are.