Who said, "Of course, you know, this means war?"

Bugs Bunny... quoting Groucho Marx

"Of course, you know, this means war!" - Groucho Marx, Duck Soup (1933) as well as Bugs Bunny, Porky's Hare Hunt (1938) and numerous other Bugs Bunny cartoons.
http://krupsjustsayin.blogspot.com/2006/01/of-course-you-know-this-means-war.html

Thus offended, (usually three times) Bugs would often drawl "Of course you know, dis means war" (a line which Jones noted was taken from Groucho Marx) and the audience gives Bugs silent permission to inflict his havoc, having earned his right to retaliate and/or defend himself.
https://en.wikipedia.org/wiki/Bugs_Bunny

Something of the kind is supposed to have been said by one old member of the MCC (Marylebone Cricket Club) to another when they saw the bust of W G Grace being removed from the Long Room at Lord’s Cricket Ground for safe keeping at the beginning of September 1939.

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