Exodus 34:16
"And thou take of their daughters unto thy sons, and their daughters go a whoring after their gods, and make thy sons go a whoring after their gods."
Cross References (ranked by relevance)
Ezra 9:2
For they have taken of their daughters for themselves, and for their sons: so that the holy seed have mingled themselves with the people of those lands: yea, the hand of the princes and rulers hath been chief in this trespass.
Nehemiah 13:25
And I contended with them, and cursed them, and smote certain of them, and plucked off their hair, and made them swear by God, saying, Ye shall not give your daughters unto their sons, nor take their daughters unto your sons, or for yourselves.
Nehemiah 13:23
In those days also saw I Jews that had married wives of Ashdod, of Ammon, and of Moab: