Explain Atticus's statement: "It's all adding up, and one of these days we are going to pay the bill for it."
In chapter 23 of To Kill a Mockingbird explain Atticus's statment: "it's all adding up, and one of these days we are going to pay the bill for it."
If one considers the historical context of Harper Lee's novel, To Kill a Mockingbird, he/she understands the import of this remark of Atticus Finch. In the same year that Miss Lee was awarded a contract to publish her work, the Civil Rights Act of 1957 was passed. This followed a successful bus boycott in 1955 staged in Montgomery, Alabama, her home state. And, with the trial of Tom Robinson modeled after the 1955 trial of two white men accused of beating Emett Till to death, but were found not guilty by an all white jury, the parallels to what occurred in the real world cannot be missed. Therefore, the line attributed to Atticus is an example of art reflecting life as Atticus utters her caution to her readers.
This chapter is actually filled with examples of foreshadowing and this is just one more of those. It has become clear that they are in the minority position in being willing to help defend Tom Robinson and the way that the prejudice and hatred of the Ewells has begun to bind people up in opposition to anyone associated with him.
This polarization has begun to really split up the town and the community and Atticus knows that at some point all of the arguing and rhetoric will boil over into action and that some of it will be directed in a negative way towards them.
What Atticus is talking about here is the racial injustice in Maycomb.
In this passage, Atticus is talking about how the whites who have all the power in Maycomb have been abusing the blacks for a long time. The whole issue of Tom Robinson getting accused is just one example of the ways in which whites treat and have treated blacks. These bits of injustice have been building up and making the blacks upset.
Atticus believes that some day, the blacks will in some way fight back. It is not clear what he means by that. One way or the other, however, black rebellion would upset the way of life that Maycomb had always known. When that happened, Maycomb would "pay the bill" for the way that they (the whites) had treated blacks over the years.