Your search for "The game is never lost till won. - George Crabbe 1754 - 1832" revealed the following:

Never cut what you can untie. - Joseph Joubert 1754 - 1824 - Magnetic Wisdoms

Do not bite at the bait of pleasure, till you know there is no hook beneath it. - Thomas Jefferson 1743 - 1826 - PWK-13.5