Commentary for Yoma 149:7
ולמאן דאמר עריות הא כתיב נאכל לישנא מעליא נקט דכתיב (משלי ל, כ) אכלה ומחתה פיה ואמרה לא פעלתי און ולמאן דאמר דגים מאי חנם דהוו מייתין להו מהפקירא דאמר מר כשהיו ישראל שואבין מים הקב"ה מזמין להם בתוך המים דגים קטנים בכדיהן
Rab and Samuel [were disputing its meaning], one said: [Fish here means] real fish; the other said: Illicit intercourse.<span class="x" onmousemove="('comment',' [I.e., they chafed under the new restrictions in matters of intercourse that had been imposed on them.]');"><sup>11</sup></span> One who said it means real fish [explains it so because of] 'which we were wont to eat'; the other who interprets it as 'illicit intercourse', does so because the term 'for nought' is used.<span class="x" onmousemove="('comment',' The suggestion is that whereas regular marriage implied widowhood (kethubah) , before that mohar (dowry, Ex. XXII, 16) , no such financial responsibility is necessary in the case of illicit intercourse.');"><sup>12</sup></span> But according to him who said it means 'intercourse', does not Scripture read: 'Which we were wont to eat'? - Scripture uses an euphemism, as it is written: She eateth and wipeth her mouth and saith: I have done no wickedness.<span class="x" onmousemove="('comment',' Prov. XXX, 20, referring to an unchaste woman.');"><sup>13</sup></span>