Why is chapter 6 an effective end to the book

The ending of this chapter is very effective. By now we have gotten to know George and Lenny. We realize that they are in fact lucky to have each other. This novel is filled with loneliness and the friendship that these two men share is rare. George has to kill his only friend. Lennie has inadvertently killed a woman and the lynch mob is coming to settle the score. Even though there is a sense of violence and fear in the air, Steinbeck makes the final scene by the river calm. There is a sad peace to it as George tells Lennie to look off into the trees. George is reciting the same story that he has recited to Lennie countless times. It has become a lullaby of sorts. It is the simple story about a home, some land and some rabbits. Then George shoots his friend in the head. It is violent but Steinbeck structures it as an act of love.