I wouldn't classify it was witty. Pithy, succinct, a truism, sure, but not particularly notable beyond who said it.

If I was looking for a witty saying by Voltaire, I would go with, "I disapprove of what you say, but I will defend to the death your right to say it." Note also that it's value is not because it is witty, which I believe it is, but because of the content of the words. Unlike your words, which I can only hope was an attempt to be witty, yet also had no content.