The grandfather tells his son to “keep up the good fight,” That means keep fighting for your rights don't give up on anything.
The conflict in this story "Battle Royal" is between the narrator's desire for what he (in a slip of the tongue) calls "social equality," or an equal chance for success in society, and the desire of white men to uphold the existing social order by humiliating and subordinating young, black men as an inferior group. In this scene, black men are forced to do what the white men want, such as