Source, in full
This is a humorous misattribution that US Senator John McCain has sometimes used since at least January 2000, but there is no indication that Mao actually ever made such a comment, which is a joke referencing the common English proverb "It's always darkest before the dawn." It has also been humorously misattributed to Franklin D. Roosevelt. The quote may be derived from the US television show The A-Team, in which it was uttered in a 1983 episode ("The Rabbit Who Ate Las Vegas") by protagonist John "Hannibal" Smith. A similar quotation is attributed to actor Paul Newman in 2003.