What evidence supports that Jem is maturing and has learned to protect the innocent? (THEME)

In Chapter 25, it is September, and Jem and Scout are about to go to sleep on their cots on the back porch. Scout sees a roly-poly bug and goes to kill it. Jem stops her, saying the bug never did anything to harm her. Scout heeds his request and carefully takes the bug outside, noting internally that if anything, Jem is becoming more like a lady than she is.

The roly-poly incident is yet another example of Jem's increasing maturity. Having witnessed Tom's trial and his family's reaction of his death, Jem has an even greater sense of the need to protect the innocent. Therefore, the roly-poly bug is a symbol of the weak and oppressed who are often "stomped on" by society. Jem believes in the equality of all people, and his choice to protect the roly-poly demonstrates how deeply ingrained this value is. Jem is becoming a young man of honor and moral virtue, just like his father.