I had always read that Jefferson said that. If you do a Google search, there must be a thousand links giving Jefferson credit for it. (Says a lot for what you get from the Internet, too.)
However, it seems that the Jefferson Encyclopedia that is loosely connected with Jefferson's Monticello attributes the quote to Gerald Ford. They state that they, "...never found such a statement in Jefferson's writings...."
Hey, what if Gerald Ford did say it? It's true enough and a little closer to our time.