Thought is the labor of the intellect, reverie is its pleasure.

[La pensée est le labeur de l’intelligence, la rêverie en est la volupté.]

Victor Hugo (1802-1885) French writer

Les Misérables, Vol. 4 “St. Denis,” Book 2 “Eponine,” ch. 1 “The Field of the Lark” (1862) [tr. Wilbour]

Alt trans. [Denny (1980)]: "Thought is the work of the intellect, reveries its self-indulgence." Cited as Part IV, ch. 2 "Eponine."