Roosevelt, Franklin D. (Franklin Delano) (1943). “Development of United States Foreign Policy: Addresses and Messages of Franklin D. Roosevelt Compiled from Official Sources, Intended to Present the Chronological Development of the Foreign Policy of the United States from the Announcement of the Good Neighbor Policy in 1933, Including the War Declarations”
Radio broadcast, 29 Dec. 1940. According to Walter Isaacson and Evan Thomas, The Wise Men (1986), this slogan was picked up for Roosevelt's address after it was used in conversation by John McCloy, who had gotten it from Jean Monnet.
Franklin D. Roosevelt (2008). “Fireside chats of Franklin Delano Roosevelt: radio addresses to the American people about the Depression, the New Deal, and the Second World War, 1933-1944”, Red & Black Pub