וַיִּרְא֤וּ בְנֵי־הָֽאֱלֹהִים֙ אֶת־בְּנ֣וֹת הָֽאָדָ֔ם כִּ֥י טֹבֹ֖ת הֵ֑נָּה וַיִּקְח֤וּ לָהֶם֙ נָשִׁ֔ים מִכֹּ֖ל אֲשֶׁ֥ר בָּחָֽרוּ׃
that the sons of nobles saw the daughters of men that they were fair; and they took them wives, whomsoever they chose.
Read halakhic rulings (Jewish law) on Genesis 6:2: and classical halakhic sources.