Commentary for Ezra 9:12

וְ֠עַתָּה בְּֽנוֹתֵיכֶ֞ם אַל־תִּתְּנ֣וּ לִבְנֵיהֶ֗ם וּבְנֹֽתֵיהֶם֙ אַל־תִּשְׂא֣וּ לִבְנֵיכֶ֔ם וְלֹֽא־תִדְרְשׁ֧וּ שְׁלֹמָ֛ם וְטוֹבָתָ֖ם עַד־עוֹלָ֑ם לְמַ֣עַן תֶּחֶזְק֗וּ וַאֲכַלְתֶּם֙ אֶת־ט֣וּב הָאָ֔רֶץ וְהוֹרַשְׁתֶּ֥ם לִבְנֵיכֶ֖ם עַד־עוֹלָֽם׃

Now therefore give not your daughters unto their sons, neither take their daughters unto your sons, nor seek their peace or their prosperity for ever; that ye may be strong, and eat the good of the land, and leave it for an inheritance to your children for ever.

Rashi on Ezra