What does section one of "Of Mice and Men" tell us about the relationship between George and Lennie? Why is it important to the novel?
This section quickly establishes the most important fact of the novel: George feels responsible for Lennie. Lennie looks up to George and wants to please him, and George wants to and feels he has to protect Lennie. The incident with the mouse proves that. Although frustrated with Lennie - mostly stemming from the scene at their last job - George feels the need to make Lennie feel better. This is why he says he'll get Lennie another mouse. Lennie is easily comforted by George. Also, the scene George alludes to from their previous job - having been run off the property because Lennie just had to touch the girl's pretty dress - proves George's loyalty to Lennie. He could easily let Lennie be caught for his behavior, however innocent it was, and then be free of the burden. But George will not. He'll stick by his friend.
This is important because it sets the stage for readers to understand the last scene of the novel. Many might misunderstand that scene and think that George was cold-blooded and simply trying to eliminate a problem for himself. However, this first scene shows that George is devoted to Lennie. His actions in the end are the actions of a friend and caretaker only.