The idle man does not know what it is to enjoy rest, for he has not earned it.

The saying contrasts restorative rest with mere idleness. Lubbock’s point is that rest becomes pleasurable and meaningful when it follows effort: work creates fatigue, purpose, and a sense of having “earned” relief, so repose feels like renewal rather than emptiness. By contrast, the idle person lacks the prior exertion that gives rest its sweetness; without a cycle of striving and recovery, leisure can turn into boredom or dullness. The aphorism also carries a moral undertone common to Victorian self-improvement literature: disciplined labor is not only socially valuable but psychologically necessary for genuine enjoyment of leisure.