As was mentioned in the previous post, Boo Radley demonstrates his courage the night of Bob Ewell's attack. Boo Radley was watching as Jem and Scout were passing his home and witnessed Bob Ewell suddenly attack them. Boo Radley courageously ran out of his home and fought with Bob Ewell to protect the children. Despite the fact that Bob was wielding a knife, Boo Radley was able to dislodge Bob's weapon and use it against him. Following the struggle, Scout recalls seeing Boo carry Jem home. Scout says,

"The man was walking with the staccato step of someone carrying a load too heavy for him. He was going around the corner. He was carrying Jem" (Lee 161).

Later on that evening, Scout explains her story to Sheriff Tate and describes the attack. She says,

"Mr. Ewell was tryin' to squeeze me to death, I reckon...then somebody yanked Mr. Ewell down..." (Lee 165).

Boo's selfless, courageous act saved Jem and Scout's lives. It was also one of the very few times that Boo Radley left his home throughout the novel. After Scout walks Boo home, she stands on his porch and thinks about her reclusive neighbor. She says,

"Boo was our neighbor. He gave us two soap dolls, a broken watch and chain, a pair of good-luck pennies, and our lives" (Lee 171).

Once feared by Jem and Scout, Boo Radley becomes the hero of the novel by its final pages, saving the children from the murderous hands of Bob Ewell. It is obvious that Boo has been keeping watch on the children for years--peeking out his own window as they played in the street and possibly even peeping in their windows at night to see if they are safe. On the Halloween night when Jem and Scout return home from the pageant, Boo must have been watching after them, coming to their rescue and killing Bob. Boo then carried the unconscious Jem home to the safety of the Finch house. Boo's courage on this night cannot be questioned. He took on a physically fit (though probably inebriated), knife-wielding man when he could have remained silent behind the walls of the Radley house. Boo risks his own life fighting Bob, a decision that ultimately puts his own precious privacy at risk.

... his (Bob's) arms were like steel. He slowly squeezed the breath out of me. I could not breathe. Suddenly, he was jerked backward and flung on the ground.  (Chapter 28, p. 262)

Atticus pays Boo the highest compliment possible when he stands face to face and tells him

"Thank you for my children, Arthur."  (Chapter 30, p. 276)

Scout never saw Boo again after that night, but she would never forget him. Boo "gave us... our lives."