The above excerpt from The Grapes of Wrath uses the rhetorical figure called parallelism, which is part of the group of the
diction figures.
In Literature, parallelism is a literary figure that consists of repeating the same structure several times changing some elements from the sentence. It is often used in order to emphasize what it is been said. What the speaker is looking for by using this method is to give balance and cadence to the idea, making it sound nicer in order to get an effect on the listener, persuading him through the repetition.
We can easily find parallelism examples in literary works as well as in everyday conversations. Here you can find some of them:
Whether at the gym, at work, or at home, she is always happy, or Easy come, easy go. Or, like the except says:
Some of the owner men were kind because they hated what they had to do, and some of them were angry because they hated to be cruel, and some of them were cold because they had long ago found that one could not be an owner unless one were cold.