Nehemiah 13:23-25

23About the same time I realized that some of the men of Judah had married women from Ashdod, Ammon, and Moab.

24Furthermore, half their children spoke the language of Ashdod or of some other people and could not speak the language of Judah at all.

25So I confronted them and called down curses on them. I beat some of them and pulled out their hair. I made them swear in the name of God that they would not let their children intermarry with the pagan people of the land.