I assume you are asking for examples of hard work shown in the novel. There are many of those. Steinbeck wanted to show the readers how hard working the migrants were. The hardships of the trip from Oklahoma to California show how hard the family works to achieve a common goal. In ch. 22, when Tom is working for Mr. Thomas, he is happy to get his hands on tools again because he wants to work. In ch. 26, when the family picks peaches, the reader sees how hard they all work for just a few pennies each. Later, when the family gets to the boxcars and jobs picking cotton, they are elated to be able to work at what most would consider back-breaking work. Ma works constantly to keep her family together even though, ultimately, much of the group is gone by the end of the novel. Throughout the story, Jim Casy is portrayed as one willing to work hard to help people. He dies trying to organize people. Oftentimes in the story, the Joads, and other characters, mention that they just want to work. Working hard is a connective thread all through the book.