Final answer:
The repeated line "Good fences make good neighbors" highlights themes of tradition and the critical examination of boundaries in human relationships as portrayed in Robert Frost's poem "Mending Wall."
Step-by-step explanation:
The repeated use of the line "Good fences make good neighbors" in literature underscores the theme of boundaries and the human relationship to them. In the context of Robert Frost's poem "Mending Wall," this line is uttered by a neighbor as a justification for maintaining a physical barrier between properties. However, the poem's speaker questions the necessity of the wall when there are no livestock to contain and hence no practical reason for the fence's existence. This repetition of the phrase suggests a generational adherence to tradition without questioning its relevance or utility. The poem challenges the reader to consider the impact of boundaries - both physical and metaphorical - on our relationships and the notion of community.