Scout's epiphany occurs as she stands upon the porch of the Radley house after walking the eremite Boo Radley home. When Scout turns from his door and, with a now mature eye, scans the neighborhood from a different perspective--"I had never see our neighborhood from this angle"--,she gains a new understanding of the once considered "haint." Boo Radley actually loves her and Jem. For, he gave them trickets and dolls that he fashioned with his own hands. And, with much understatement, Scout adds, "and our lives."
As she gazes out at her house, Scout realizes the extent of Boo Radley's love; he has braved the wrath of his brother, he has of necessity temporarily overcome his fear of others--all for his brotherly love for Jem and Scout as he has felt that he had to protect them at all costs. Truly, Boo has exemplified the willingness to fulfill a verse from the New Testament of the Bible,
Greater love hath no man than this, that a man lay down his life for his friends. [John 15:13]
It is at this moment that Scout has followed her father's advice from Chapter 3; she has climbed into Boo's skin and has felt the kindness of his nature. Scout, too, recognizes that she and Jem have not reciprocated his love,
We never put back into the tree what we took out of it: we had given him nothing, and it made me sad.
As Scout walks home, she narrates that she feels "very old" because she has greatly matured from hers and Jem's frightening encounter with Bob Ewell as well as her new insights into the character of Boo Radley.