Atticus, why does Burris Ewell not have to go to school while I do?
This overall scene shows grace because Atticus caught the kids doing something they clearly were not supposed to be doing and didn't give them the punishment they deserved
Fine w'll slow it down a while
Jem, what were you doing?
Son, I'm going to tell you something and tell you one time: stop tormenting that man. That goes for the other two of you
This connects to grace because the common folk graciously turned a blind eye to the actions of the Ewells even though they should not have. They decided to just let them be instead of punishing them.
You, Miss Scout Finch, are a part of the common folk. You must obey the law.
The Ewells are a part of a special society of people only made up of the Ewells. In certain circumstances, the common folk judiciously allowed them certain privileges by the simple method of becoming blind to them.