That happy age when a man can be idle with impunity.

Irving’s line wryly celebrates a stage of life—typically youth or early adulthood—when one can afford to be “idle” without paying a social, financial, or moral penalty. The phrase “with impunity” sharpens the irony: idleness is treated as a minor transgression that later life will punish through responsibility, reputation, or necessity. Read this way, the quote is less an endorsement of laziness than a nostalgic (and slightly satirical) observation about how society tolerates leisure in some seasons of life but condemns it in others. It also hints at Irving’s broader interest in manners and the passage of time, where freedom is often fleeting and retrospectively idealized.