Industry is not only the instrument of improvement, but the foundation of pleasure. He who is a stranger to it may possess, but cannot enjoy, for it is labor only which gives relish to pleasure. It is the indispensable condition of possessing a sound mind in a sound body, and it is the appointed vehicle of every good to man.

Advice to Youth: Containing a Compendium of the Duties of Human Life, in Youth and Manhood (ed. 1837)