Mamzer

     Deuteronomy 23:3 לֹא־יָבֹ֥א מַמְזֵ֖ר בִּקְהַ֣ל יְהֹוָ֑ה גַּ֚ם דּ֣וֹר עֲשִׂירִ֔י לֹא־יָ֥בֹא ל֖וֹ בִּקְהַ֥ל יְהֹוָֽה׃ {ס}   

No one misbegotten shall be admitted into the congregation of יהוה; no descendant of such, even in the tenth generation, shall be admitted into the congregation of יהוה.

Kiddushin 71a:2

אָמַר רַבִּי יְהוֹשֻׁעַ בֶּן לֵוִי כֶּסֶף מְטַהֵר מַמְזֵרִים שֶׁנֶּאֱמַר וַיֵּשֶׁב מְצָרֵף וּמְטַהֵר כֶּסֶף מַאי מַגִּישֵׁי מִנְחָה בִּצְדָקָה אָמַר רַבִּי יִצְחָק צְדָקָה עָשָׂה הַקָּדוֹשׁ בָּרוּךְ הוּא עִם יִשְׂרָאֵל שֶׁמִּשְׁפָּחָה שֶׁנִּטְמְעָה נִטְמְעָה

Rabbi Yehoshua ben Levi says: Money purifies mamzerim. Money causes rich mamzerim to become assimilated with Jews of unflawed lineage, since other families marry them despite their flawed lineage. In the future, God will not single them out as mamzerim, as it is stated: “And he shall sit as a refiner and purifier of silver,” which teaches that money, i.e., silver, purifies them.

Chizkuni, Deuteronomy 23:3:1-2

לא יבא ממזר הואיל ונשרש בעבירה כמו כרת יפסל הוא וזרעו. ממזר שנולד ממי שהוא זר אצל אמו.

'לא יבא ממזר בקהל ה, “a bastard must not marry a Jewish woman;” seeing that he is a product of a union punishable by extinction of its seed, what point is there in such a male impregnating a Jewish woman with his seed? The definition of a mamzer from the root זר, alien, is someone whose mother was out of bounds to the male who had impregnated her.

Mishneh Torah, Forbidden Intercourse 15:7-13

מַמְזֵר מֻתָּר לִשָּׂא גִּיֹּרֶת. וְכֵן הַמַּמְזֶרֶת מֻתֶּרֶת לְגֵר. וְהַבָּנִים מִשְּׁנֵיהֶם מַמְזֵרִים שֶׁהַוָּלָד הוֹלֵךְ אַחַר הַפָּגוּם שֶׁנֶּאֱמַר (דברים כג ג) "בִּקְהַל ה'" וּקְהַל גֵּרִים אֵינוֹ קָרוּי (דברים כג ג) "קְהַל ה'": גִּיֹּרֶת שֶׁנִּשֵּׂאת לְגֵר וְהוֹלִידוּ בֵּן אַף עַל פִּי שֶׁהוֹרָתוֹ וְלֵדָתוֹ בִּקְדֻשָּׁה הֲרֵי זֶה מֻתָּר בְּמַמְזֶרֶת. וְכֵן בֶּן בֶּן בְּנוֹ עַד שֶׁיִּשְׁתַּקַּע שֵׁם גֵּרוּתוֹ מִמֶּנּוּ וְלֹא יִוָּדַע שֶׁהוּא גֵּר וְאַחַר כָּךְ יֵאָסֵר בְּמַמְזֶרֶת. וְאֶחָד הַגֵּרִים וְאֶחָד הָעֲבָדִים מְשֻׁחְרָרִין דִּין אֶחָד לְכֻלָּן: …

7. A mamzer may marry a female convert and a female mamzer may marry a male convert, the offspring of both relationships are mamzerim. For the status of the offspring follows that of the blemished one. [The license for such a marriage is derived from] the verse: "[A mamzer shall not enter] God's congregation." (Deut. 23:3) The congregation of converts is not considered as "God's congregation." (ibid) 8. When a female convert marries a male convert and gives birth to a son, he is permitted to marry a female mamzer even though he was both conceived and born in holiness…

Chagigah 9a:5

רַבִּי שִׁמְעוֹן בֶּן מְנַסְּיָיא אוֹמֵר: אֵיזֶהוּ מְעֻוּוֹת שֶׁאֵינוֹ יָכוֹל לְהִתָּקֵן? זֶה הַבָּא עַל הָעֶרְוָה וְהוֹלִיד מִמֶּנָּה מַמְזֵר. אִם תֹּאמַר בְּגוֹנֵב וְגוֹזֵל — יָכוֹל הוּא לְהַחְזִירוֹ, וִיתַקֵּן.

Rabbi Shimon ben Menasya says: Who is the crooked that cannot be made straight? This verse is referring to one who engaged in intercourse with a woman forbidden to him and fathered a mamzer with her. This individual is unable to rectify his sin, because the status of the illegitimate child is permanent. And if you say that it is referring to one who steals or robs, although he is crooked he can return what he stole and in this manner his sin will be rectified.