Only recorded in English from North American sources. Cf. Du. wie a zegt , moet ook b zeggen . 1838 Charcoal Sketches 190 Not so easy as you think … If you say A, they'll make you say B. 1988 Washington Times 16 Sept. F3 But who says ‘A’ must say ‘B’, Mr. McCarthy. You can't talk about victims and caring and knowing cows individually while, at the same time, you treat carrots as nobodies! 1996 National Review 2 Sept. 103 Yet who says A, the adage goes, must say B. If you are going to deny something, you may find yourself having to deny it ardently. action and cosequence ; necessity