In Victor Hugo's "The Hunchback of Notre-Dame," the quote "When one does wrong, one must do it thoroughly" reflects the idea that actions, especially those of a negative or immoral nature, should be undertaken with full awareness of their consequences. This suggests a certain seriousness in engaging in wrongdoing, highlighting the complexity of human morality and the weight of choices made. It implies that if one chooses a path of wrongdoing, they should not pursue it half-heartedly, indicating a sense of accountability in moral transgressions.

This statement resonates throughout the novel, as characters grapple with their decisions and the repercussions they face. The characters' struggles illuminate themes of guilt, redemption, and the consequences of their actions, showing how moral choices can be all-encompassing. Hugo's narrative encourages readers to reflect on the nature of evil and the importance of conscious choice in life's moral landscape, urging a deeper understanding of the paths one decides to take.