Attributed in Patton (motion picture) (1970). This is sometimes said to have been uttered in a speech by Patton to the Sixth Armored Division of the Third Army, 31 May 1944, but documentation is lacking. The following poem appeared in the Bureau of Aeronautics Navy Department News Letter, 1 Jan. 1943: "The greatest duty of a sailor / Is duty from worries and cares, / Not to die for his country, / Make our enemies die for theirs!"
Barbara Wertheim Tuchman, Center for the Book, Authors' League of America (1980). “The Book: A Lecture Sponsored by the Center for the Book in the Library of Congress and the Authors' League of America, Presented at the Library of Congress October 17, 1979”, Library of Congress