Throughout Grapes of Wrath, Ma is the one who tries to hold her family together, even as they are falling apart. She, at the beginning of the story and nearly to the end, sees her family as the most important thing and at any cost, she struggles to keep them together. When the family meets with one problem after another, Ma says that they are "holdin' on", meaning that they haven't completely fallen apart yet; that they still have one another to lean on for support. It isn't until Tom leaves to continue Casy's efforts to organize people and to help people, that Ma begins to see that the family of mankind is even more important than the nuclear family, so that "holdin' on" then comes to mean working with all of mankind to get through the tough times. This point is brough home sharply in the final, stark scene of Rose of Sharon nursing the dying man the family has just met in the barn. They don't know this man, but they know he is starving, so they do what they can for him.