Tom's parting words to Ma in Chapter 28 echo both themes:
"Wherever they’s a fight so hungry people can eat, I’ll be there. Wherever they’s a cop beatin’ up a guy, I’ll be there. If Casy knowed, why, I’ll be in the way guys yell when they’re mad an’—I’ll be in the way kids laugh when they’re hungry n’ they know supper’s ready. An’ when our folks eat the stuff they raise an’ live in the houses they build—why, I’ll be there. See?"
And they also remind me of Christ's description of the "sheep" in Matthew 28:34-40:
"Then the King will say to those on his right, 'Come, you who are blessed by my Father; take your inheritance, the kingdom prepared for you since the creation of the world. For I was hungry and you gave me something to eat, I was thirsty and you gave me something to drink, I was a stranger and you invited me in, I needed clothes and you clothed me, I was sick and you looked after me, I was in prison and you came to visit me.'
Then the righteous will answer him, 'Lord, when did we see you hungry and feed you, or thirsty and give you something to drink? When did we see you a stranger and invite you in, or needing clothes and clothe you? When did we see you sick or in prison and go to visit you?
The King will reply, 'I tell you the truth, whatever you did for one of the least of these brothers of mine, you did for me.'"