Reference for Kiddushin 155:20

וכולן מקרא אחד דרשו (יחזקאל מד, כב) אלמנה וגרושה לא יקחו להם לנשים כי אם בתולות מזרע בית ישראל רבי יהודה סבר עד דאית כל זרע מישראל רבי אליעזר בן יעקב סבר מזרע ואפילו מקצת זרע

And so the argument revolves: the distinguishing feature of one is not that of the other; the feature common to both is that they are not as the majority of the community; so also do I adduce the proselyte, who is not as the majority of the community, and his daughter is unfit! [No:] what is the feature common to both? That they have an element<span class="x" onmousemove="('comment',' Lit., 'side'.');">²⁸</span>

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