What is the overall message in Steinbeck's Of Mice and Men, given that the author continuously illustrates friendship, commitment and relationship throughout the novel?
Friendship and commitment are at the heart of this story and are shown most clearly through the relationship between Lennie and George. Through these two characters, Steinbeck presents his central message: friendships are often strengthened by difficult conditions, like poverty and powerlessness, but they cannot always overcome such tests.
From the very beginning of the story, it is clear that their friendship is based on unequal footing. George, for example, is like a father figure to Lennie, and Lennie relies on George to take care of him. Despite this, they are united (and strengthened) by their dream to own their own ranch and live off "the fatta the lan'." This causes some suspicion and interest from other characters in the story: remember that in Chapter Two, for instance, Slim comments that not many men travel around together. But this attitude does not affect George and Lennie: they are more determined than ever to achieve their dream and make a successful life together. Even when Curley takes an instant dislike to Lennie, their friendship holds strong and their commitment to each other is unaffected.
George and Lennie's friendship (and their dream of owning a ranch) is so strong that it attracts other characters in the story. Both Crooks and Candy, for example, are drawn in by the dream of owning a ranch and plan on becoming part of George and Lennie's brotherhood.
But when Lennie kills Curley's wife, it becomes clear that no amount of friendship or commitment can save him. Even though her death was accidental, George cannot stop the men from hunting him down and shooting him. This not only brings their friendship to a tragic end but also makes it clear that these men will never overcome the poverty and powerlessness which is inherent in their lives.