וְלָקַחְתָּ֥ מִבְּנֹתָ֖יו לְבָנֶ֑יךָ וְזָנ֣וּ בְנֹתָ֗יו אַחֲרֵי֙ אֱלֹ֣הֵיהֶ֔ן וְהִזְנוּ֙ אֶת־בָּנֶ֔יךָ אַחֲרֵ֖י אֱלֹהֵיהֶֽן׃
and thou take of their daughters unto thy sons, and their daughters go astray after their gods, and make thy sons go astray after their gods.
Read halakhic rulings (Jewish law) on Exodus 34:16: and classical halakhic sources.