John Ford shot this legendary scene in one take:
Ma: How am I gonna know about ya, Tommy? They could kill ya and I'd never know. They could hurt ya. How am I gonna know?
Tom: Maybe it's like Casey says. A fellow ain't got a soul of his own, just little piece of a big soul, the one big soul that belongs to everybody, then -
Ma: Then what, Tom?
Tom: Then it don't matter. I'll be all around in the dark. I'll be everywhere, wherever you can look. Wherever there's a fight so hungry people can eat, I'll be there. Wherever there's a cop beatin' up a guy, I'll be there. I'll be in the way guys yell when they're mad. I'll be in the way kids laugh when they're hungry and they know supper's ready and where people are eatin' the stuff they raise and livin' in the houses they build. I'll be there, too.
(Henry Fonda as Tom Joad, Jane Darwell as Ma in "The Grapes of Wrath")