מַה־נַּעֲשֶׂ֥ה לָהֶ֛ם לַנּוֹתָרִ֖ים לְנָשִׁ֑ים וַאֲנַ֙חְנוּ֙ נִשְׁבַּ֣עְנוּ בַֽיהוָ֔ה לְבִלְתִּ֛י תֵּת־לָהֶ֥ם מִבְּנוֹתֵ֖ינוּ לְנָשִֽׁים׃
How shall we do for wives for them that remain, seeing we have sworn by the LORD that we will not give them of our daughters to wives?’
Read midrashic interpretation of Judges 21:7: and classical rabbinic exegesis.