Reference for Pesachim 230:5

אלא מאי הכא איתמר נטילת ידים תרי זימני למה לי הא משא ליה ידיה חדא זימנא אמרי כיון דבעי למימר אגדתא והלילא דילמא אסוחי אסחיה לדעתיה ונגע

Surely he has [already] washed his hands once?<span class="x" onmousemove="('comment',' Knowing that he would eat vegetables a second time; hence once should suffice.');">⁸</span> Said R'Papa to them: On the contrary, it was stated here, for if you should think that it was stated in general, why two dippings?<span class="x" onmousemove="('comment',' The vegetable having been dipped once into vinegar, it need not be dipped again.');">⁹</span> What then?

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