Intermarriage: A Mitzvah
1.

(ג) וְלֹ֥א תִתְחַתֵּ֖ן בָּ֑ם בִּתְּךָ֙ לֹא־תִתֵּ֣ן לִבְנ֔וֹ וּבִתּ֖וֹ לֹא־תִקַּ֥ח לִבְנֶֽךָ׃

(ד) כִּֽי־יָסִ֤יר אֶת־בִּנְךָ֙ מֵֽאַחֲרַ֔י וְעָבְד֖וּ אֱלֹהִ֣ים אֲחֵרִ֑ים וְחָרָ֤ה אַף־יְהוָה֙ בָּכֶ֔ם וְהִשְׁמִידְךָ֖ מַהֵֽר׃

(3) neither shalt thou make marriages with them: thy daughter thou shalt not give unto his son, nor his daughter shalt thou take unto thy son. (4) For he will turn away thy son from following Me, that they may serve other gods; so will the anger of the LORD be kindled against you, and He will destroy thee quickly.

כי יסיר את בנך מאחרי. בנו של גוי כשישא את בתך, יסיר את בנך אשר תלד לו בתך מאחרי למדנו שבן בתך הבא מן הגוי קרוי בנך, אבל בן בנך הבא מן הגויה אינו קרוי בנך אלא בנה, שהרי לא נאמר על בתו לא תקח כי תסיר את בנך מאחרי:
ולדה כמותה מנלן

...how do we know that the issue [of a Gentile woman] takes her status?...because Scripture says, "neither shalt thou make marriages with them" (Deuteronomy 7:3) How do we know that her issue bears her status? — R. Johanan said on the authority of R. Simeon b. Yohai, Because Scripture says, "For he will turn away thy son from following me" (ibid): thy son by an Israelite woman is called thy son, but thy son by a heathen is not called thy son....

2.

(י) וַיֵּצֵא֙ בֶּן־אִשָּׁ֣ה יִשְׂרְאֵלִ֔ית וְהוּא֙ בֶּן־אִ֣ישׁ מִצְרִ֔י בְּת֖וֹךְ בְּנֵ֣י יִשְׂרָאֵ֑ל וַיִּנָּצוּ֙ בַּֽמַּחֲנֶ֔ה בֶּ֚ן הַיִּשְׂרְאֵלִ֔ית וְאִ֖ישׁ הַיִּשְׂרְאֵלִֽי׃

(יא) וַ֠יִּקֹּב בֶּן־הָֽאִשָּׁ֨ה הַיִּשְׂרְאֵלִ֤ית אֶת־הַשֵּׁם֙ וַיְקַלֵּ֔ל וַיָּבִ֥יאוּ אֹת֖וֹ אֶל־מֹשֶׁ֑ה וְשֵׁ֥ם אִמּ֛וֹ שְׁלֹמִ֥ית בַּת־דִּבְרִ֖י לְמַטֵּה־דָֽן׃

(יב) וַיַּנִּיחֻ֖הוּ בַּמִּשְׁמָ֑ר לִפְרֹ֥שׁ לָהֶ֖ם עַל־פִּ֥י יְהוָֽה׃

(יג) וַיְדַבֵּ֥ר יְהוָ֖ה אֶל־מֹשֶׁ֥ה לֵּאמֹֽר׃

(יד) הוֹצֵ֣א אֶת־הַֽמְקַלֵּ֗ל אֶל־מִחוּץ֙ לַֽמַּחֲנֶ֔ה וְסָמְכ֧וּ כָֽל־הַשֹּׁמְעִ֛ים אֶת־יְדֵיהֶ֖ם עַל־רֹאשׁ֑וֹ וְרָגְמ֥וּ אֹת֖וֹ כָּל־הָעֵדָֽה׃

(טו) וְאֶל־בְּנֵ֥י יִשְׂרָאֵ֖ל תְּדַבֵּ֣ר לֵאמֹ֑ר אִ֥ישׁ אִ֛ישׁ כִּֽי־יְקַלֵּ֥ל אֱלֹהָ֖יו וְנָשָׂ֥א חֶטְאֽוֹ׃

(טז) וְנֹקֵ֤ב שֵׁם־יְהוָה֙ מ֣וֹת יוּמָ֔ת רָג֥וֹם יִרְגְּמוּ־ב֖וֹ כָּל־הָעֵדָ֑ה כַּגֵּר֙ כָּֽאֶזְרָ֔ח בְּנָקְבוֹ־שֵׁ֖ם יוּמָֽת׃

(10) And the son of an Israelitish woman, whose father was an Egyptian, went out among the children of Israel; and the son of the Israelitish woman and a man of Israel strove together in the camp. (11) And the son of the Israelitish woman blasphemed the Name, and cursed; and they brought him unto Moses. And his mother’s name was Shelomith, the daughter of Dibri, of the tribe of Dan. (12) And they put him in ward, that it might be declared unto them at the mouth of the LORD. (13) And the LORD spoke unto Moses, saying: (14) ’Bring forth him that hath cursed without the camp; and let all that heard him lay their hands upon his head, and let all the congregation stone him. (15) And thou shalt speak unto the children of Israel, saying: Whosoever curseth his God shall bear his sin. (16) And he that blasphemeth the name of the LORD, he shall surely be put to death; all the congregation shall certainly stone him; as well the stranger, as the home-born, when he blasphemeth the Name, shall be put to death.

Rambam - Maimonides: Matrilineal descent began from 'The Covenant Between The Pieces'.

Tosafot - Matrilineal descent began from Mt. Sinai