Commentary for Yevamot 4:13
אֵיזֶהוּ מַמְזֵר, כָּל שְׁאֵר בָּשָׂר שֶׁהוּא בְלֹא יָבֹא דִּבְרֵי רַבִּי עֲקִיבָא. שִׁמְעוֹן הַתִּימְנִי אוֹמֵר, כָּל שֶׁחַיָּבִין עָלָיו כָּרֵת בִּידֵי שָׁמַיִם. וַהֲלָכָה כִדְבָרָיו. רַבִּי יְהוֹשֻׁעַ אוֹמֵר, כָּל שֶׁחַיָּבִים עָלָיו מִיתַת בֵּית דִּין. אָמַר רַבִּי שִׁמְעוֹן בֶּן עַזַּאי, מָצָאתִי מְגִלַּת יֻחֲסִין בִּירוּשָׁלַיִם וְכָתוּב בָּהּ, אִישׁ פְּלוֹנִי מַמְזֵר מֵאֵשֶׁת אִישׁ, לְקַיֵּם דִּבְרֵי רַבִּי יְהוֹשֻׁעַ. אִשְׁתּוֹ שֶׁמֵּתָה, מֻתָּר בַּאֲחוֹתָהּ. גֵּרְשָׁהּ וָמֵתָה, מֻתָּר בַּאֲחוֹתָהּ. נִשֵּׂאת לְאַחֵר וָמֵתָה, מֻתָּר בַּאֲחוֹתָהּ. יְבִמְתּוֹ שֶׁמֵּתָה, מֻתָּר בַּאֲחוֹתָהּ. חָלַץ לָהּ וָמֵתָה, מֻתָּר בַּאֲחוֹתָהּ:
Which is a mamzer? (The child of) any kin with whom marriage is interdicted. These are the words of R. Akiva. Shimon Hatemani says: (The child of) all kin with whom marriage is interdicted by kareth at the hands of heaven, [but not (merely) by negative commandment]. And this is the halachah [i.e., that the child of a kareth-interdicted marriage is a mamzer (except the child of a niddah), but the child of a marriage interdicted by negative commandment (alone) is not a mamzer.] R. Yehoshua says: All kin with whom marriage is interdicted by judicial death penalty. R. Shimon b. Azzai said: I found a pedigree-scroll in Jerusalem, in which it was written: "Such and such is a mamzer from an adulterous union (in confirmation of the word of R. Yehoshua.) If one's wife died, he may marry her sister. If he divorced her and she died, he may marry her sister. If she married another and she died, he may marry her sister. If one's yevamah died, he may marry her sister. If he gave her chalitzah and she died, he may marry her sister.
Bartenura on Mishnah Yevamot
English Explanation of Mishnah Yevamot
Bartenura on Mishnah Yevamot
English Explanation of Mishnah Yevamot
Rabbi Shimon ben Azzai said: I found a scroll of genealogical records in Jerusalem, and it was written on it, “So-and-so is a mamzer [having been born] from an adulterous woman”, which confirms the view of Rabbi Joshua. In this section there are three opinions as to which type of forbidden unions create mamzers. Rabbi Akiva’s opinion is the strictest: any forbidden union of an incestuous nature creates a mamzer. This would preclude only forbidden unions that are not incestuous, such as a kohen and a divorcee. Shimon the Yemenite (who is not called rabbi) holds that any forbidden union punishable by kareth creates a mamzer. Shimon the Yemenite rejects Rabbi Akiva and holds that forbidden unions that are merely prohibited but not punishable by kareth or death do not create mamzers. An example of such a case is a shomeret yavam who gets remarried to an outsider without first having yibbum or halitzah with her yavam. According to Rabbi Akiva the child of such a marriage is a mamzer and according to Shimon the Yemenite the child is not. Interestingly, the mishnah explicitly states that the halakhah is according to this view. This is one of the few times that the Mishnah makes such a remark. Rabbi Joshua is even more lenient concerning the creation of mamzers. Only a union punishable by death creates mamzers. Rabbi Shimon ben Azzai claims that he found a scroll of genealogical records in which it was recorded that So-and-so was a mamzer because he was the son of an adulterous affair, which is punishable by death. From here he concludes that the halakhah is like Rabbi Joshua. However, Rabbi Akiva and Shimon the Yemenite could both claim that just because this mamzer was from an adulterous affair punishable by death does not prove that the halakhah is like Rabbi Joshua.