Reference for Yevamot 155:4

ת"ר אם נאמר בנים למה נאמר דורות ואם נאמר דורות למה נאמר בנים אם נאמר בנים ולא נאמר דורות הייתי אומר בן ראשון ושני אסור שלישי מותר לכך נאמר דורות

Our Rabbis taught: If the expression of sons<span class="x" onmousemove="('comment',' Cf. Deut. XXIII, 9: The sons (E.V., children) that are born&nbsp;… the third generation. ');">¹³</span> was used, why was also that of generations<span class="x" onmousemove="('comment',' Cf. Deut. XXIII, 9: The sons (E.V., children) that are born&nbsp;… the third generation. ');">¹³</span> used; and if that of generations was used, why also that of sons?<span class="x" onmousemove="('comment',' Either the one expression or the other should have been used throughout the context. ');">¹⁴</span> If the expression of 'sons' had been used and not that of 'generations'<span class="x" onmousemove="('comment',' The text reading the 'third son' instead of third generation. ');">¹⁵</span>

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