Reference for Bava Metzia 138:2

(אמר ליה לא אמר ליה) חמרא כולי עלמא ידעי דאיכא דבסים ואיכא דלא בסים

it is certainly necessary to inform him [of the grounds of my verdicts]: As for coins, would he take good coins and leave short-weight ones [for you]? But in the case of wine, everybody knows that some wine is sweet and some is not.<span class="x" onmousemove="('comment',' Hence there can be no question of unfair division of money, as there may be in respect of wine. ');">²</span>

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