"This case is closed. I can't find against you, Snopes, but I can give you advice. Leave this country and don't come back." (13)
The Justice has discretion to exercise his judgment on Abner, even though there isn't enough evidence to hold him accountable for his actions legally.
"Barn burner!" (16)
We know that the speaker of this judgment is "half again [Sarty's] size" (17). In the same way that Sarty believes his father's enemy's are his own, this kid thinks that if a father is a barn burner, the sons must be too.
"You were fixing to tell them. You would have told them." (29)
Since we know that Sarty did plan to lie for his father, we can feel the brutal sting of this injustice. Sarty probably realizes that if he wants his father to think he's a loyal son, he'll have to spend his life proving it to him.
"You done the best you could!" he cried. (64)
Even though we don't like Abner, it's heartwarming to see Sarty gain empathy for him. It shows that Sarty is deeply concerned with fairness. He thinks his father's cleaning of the rug was a gesture of good faith, which de Spain has rejected.
[De Spain] wore [..] an expression of […] amazed unbelief […] at the incredible circumstance of being sued by one of his own tenants (71).
The narrator suggests that tenant farmers had access to legal process, but rarely used it. Abner did create the whole mess in the first place, but he does seem to be setting a good example for others in his situation, at least on this one issue. If tenant farmers would exercise their rights to pursue legal action against their landlords, the landlords might be less likely to take advantage of them.
"He was brave!" (108)
Sarty's judgment on his father here seems to be heartfelt. He cites his father's war activities as evidence of the man's bravery, and the narrator wonders if Sarty would still find his father brave if he knew the truth. We think Sarty's judgment goes deeper. In time he will probably realize that his father was both brave, and a coward.