The philosopher George Santayana wrote (in The Life of Reason, 1905), "Those who cannot remember the past are condemned to repeat it." The main idea of this quote is that the past contains both patterns and valuable lessons. The type of memory Santayana is referring to is what is called "social memory," which includes commemoration through ceremonies, writings, monuments, and even songs. This quote also means that if an effort to effect change does not succeed, the heirs must persevere and innovate until the goal is achieved.
One way Ernest Gaines's novel embodies the saying is by recording the fictional chronicle of Jane Pittman, through the editor's retelling. The idea that one woman's story is worth preserving, especially because she was "ordinary" and she survived the horror of enslavement, bears out the idea of remembering as key to avoid repeating, in this case, the devastating history of a country that practiced slavery.
Another way to approach the theme would be to focus on two characters who live similarly but at different times. Two men who give their lives while fighting for civil rights offer a good example. Ned Douglass personifies an earlier generation of activist, in the 1920s to 1930s, while Jimmy Aron, a generation later, both benefited and departed from Ned's example. Although they both were killed, Miss Jane was inspired by them to continue and take more risks as she got older.