Reference for Bekhorot 110:3

הנהו סולמי דפרת נינהו

But is it not written: And as to the fourth river it is the Euphrates?<span class="x" onmousemove="('comment',' Gen. II, 14 thus proving that the Euphrates is one of the rivers, and you say that they all issue from it.');">²</span>

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