Atticus does work hard for his children. He takes Tom Robinson’s case partly as an example to them. He explains that he would not be able to hold his head up or tell them what to do if he didn’t.
Scout asks Atticus why she is defending Tom Robinson even though he knows he will lose. He does tell her that just because you can’t win is not a reason to avoid doing something, but he also tells her that he has to set an example.
"For a number of reasons," said Atticus. "The main one is, if I didn't I couldn't hold up my head in town, I couldn't represent this county in the legislature, I couldn't even tell you or Jem not to do something again." (ch 9)
Atticus feels that he needs to set an example for the town and for his children. He wants his children to be proud of him, but he also wants them to be good people. He wants them to do as he would do, and look at the world as he does.