from Wikiquote:

"I disapprove of what you say, but I will defend to the death your right to say it."

* Though these words are regularly attributed to Voltaire, they were first used by Evelyn Beatrice Hall, writing under the pseudonym of Stephen G Tallentyre in The Friends of Voltaire (1906), as a summation of Voltaire's beliefs on freedom of thought and expression.

* Another possible source for the quote was proposed by Norbert Guterman, editor of "A Book of French Quotations," who noted a letter to M. le Riche (February 6, 1770) in which Voltaire is quoted as saying: "Monsieur l'abbé, I detest what you write, but I would give my life to make it possible for you to continue to write." This remark, however, does not appear in the letter.