The Illustrated Book of Manners: A Manual of Good Behavior and Polite Accomplishments, 1866

“I may not approve this man’s acts,” he said; “they may be contrary to my judgement, and offend my taste, but I would shoulder a musket tomorrow in defense of his right to do as he pleases..”

A side note: Evelyn Beatrice Hall wrote in The Friends of Voltaire, published in 1907, “I disapprove of what you say, but I will defend to the death your right to say it”. This quote was often misattributed to Voltaire himself, but was written by Hall. However, it looks like some version of the quote predates her book by at least 40 years.